Software Reserve copy .

Purchasing suitable equipment is a necessary, but not sufficient condition for building a backup infrastructure. Another important part of the problem isselection of specialized software that will serve as a logical basis for protecting data from destruction.

If you need to back up a single user's files, standard utilities such as Ntbackup on Windows or tar on Unix systems are usually sufficient. They can be used to set the backup method and determine whether files have changed (required when performing selective backups), but their use across the entire enterprise does not seem appropriate.

For small companies, you can often do without special software at all. For backup with the minimum required functionality, it is supplied with the OS (this statement is true for both MS Windows and UNIX), and with the Oracle DBMS, for example, a truncated version of Legato Networker is supplied.

Medium and large companies need to have a well-organized backup infrastructure with high degrees of integration and automation; they have to purchase specialized software with client-server architecture.

When with corporate information systems the situation becomes significantly more complicated. They include a large number of different computers that use special technologies: file servers, database servers, and the like. Backing up information on them requires special technological solutions. In addition, for corporate information systems it is important not only to preserve user information, but also to restore the functionality of computers and servers as quickly as possible in the event of any, even hardware failures. This allows you to avoid long downtime for employees and associated company losses.

It is obvious that for the successful operation of the entire backup complex it is necessary coordinated work of both software and hardware. Therefore, standard backup tools are not used for enterprise-scale backup systems. There are several important requirements that data backup and recovery software for large enterprises must satisfy:
- Building a system based on the client-server principle. Since any modern information system is based on a network, the backup system must also be network-based. Such a system should provide: backup management throughout the entire network from dedicated computers; remote backup of data contained on servers and workstations; centralized use of backup devices. When applied to backup, client-server terminology means the following: the component of the backup system that provides control of all processes and devices is called the server, and the component responsible for saving or restoring specific data is called the client. An enterprise-scale backup software product must ensure the coordinated operation of all elements of a computer network - workstations, servers and backup devices - to ensure the least load on devices and communication channels. To do this, the following organization of the software package is used: system server, management console (in general, not installed on the server), backup agents (client programs installed on workstations). In addition, such a product must provide the ability to work with clients running different operating systems. Finally, such programs must provide access to user and database files, even if those files are open and in use by the system.
- Multiplatform. Modern information network is heterogeneous. Accordingly, the backup system must fully function in such a network, i.e. it is assumed that its server part will work in various operating environments and support clients on a variety of hardware and software platforms. Availability, at a minimum, of clients for different operating systems.
- Automation of typical operations. The backup process inevitably involves many cycles of different operations. The backup system should perform cyclic work automatically and minimize the number of manual operations. In particular, it must support: scheduled backups, media rotation, scheduled maintenance of backup devices. For example, copying can be done every day on certain time. Another example of a cycle is the process of overwriting information on backup media. If daily backup copy should be stored for a week, then after this period the corresponding media can be used again. This process of sequentially replacing backup media is called rotation. Cyclic work also includes preventive maintenance of backup devices, for example, cleaning the components of the tape drive mechanism of the tape drive after a certain period of operation using a special cassette. It should be noted that automation of work is one of the key factors in reducing the cost of maintaining a backup system.
- Supports various backup modes. Let's say that every day you need to back up a certain set of files, such as those contained in the same directory. As a rule, changes are made only to individual files during the working day, and daily copying of information that has remained unchanged since the previous backup was created is unnecessary. Based on this, the system must provide various backup modes, i.e., support the ability to save only the information that has been changed since the previous copy was created.
- Easy installation, support for a wide range of drives, quick recovery of network servers after a disaster. A network server may fail for various reasons, for example due to a system crash hard drive or due to software errors leading to the destruction of system information. In this case, restoring it requires reinstalling the OS, configuring devices, installing applications, restoring the file system and user accounts. All these operations are very labor-intensive, and errors may occur at any stage of this process. Thus, to restore a server, it is necessary to have a backup copy of all information stored on it, including system data, in order to bring it back to working condition as quickly as possible.
-Availability of modules for major DBMS (MS-SQL, Oracle, DB/2) and business-critical applications (MS Exchange, SAP R/3, etc.); online data backup. Often, an information system includes various client-server applications that must function around the clock. Examples of this are email systems, collaboration systems (for example, Lotus Notes) and SQL servers. It is impossible to back up the databases of such systems using conventional means, since they are open all the time. Therefore, they often have their own backup tools built in, but their use, as a rule, does not fit into the overall technology adopted by the organization. Based on this, the backup system must ensure that client-server application databases are saved online.
- Possibility of both central and local administration, developed monitoring and management tools. To manage backup processes and monitor their status, the backup system must have graphical monitoring and control tools and a wide range of event notification tools, and a function for generating and distributing reports.
Based on the requirements above, enterprise backup software must be superior to an SMB (Small/Medium Business) solution. However, it also requires significantly higher acquisition costs, as well as training costs. For this reason, when choosing a product, you should consider the advanced and additional functions and technology. For small existing solutions that can no longer be scaled up due to new requirements, all leading vendors offer software upgrades to enterprise-class products, and disk backup is considered particularly important features for large enterprises, as they significantly improve backup performance and provide additional features data protection.

Popular solutions for the corporate sector are HP Data Protector, Bakbone NetVault, BrightStor ARCserve Backup (Computer Associates), Legato NetWorker, Veritas NetBackup and some others. Many of these products are deservedly popular in Russia. All of them are designed to work in heterogeneous environments with different types of operating systems and large volumes of data and meet high requirements for performance, stability and availability. Therefore, support for storage area networks is a mandatory component of these products. Through multiplexing, enterprise backup solutions provide high performance, support multiple libraries and drives, and can be tailored to specific needs using database agents and operating systems. The type of software in question is a set of additional features that either come with the storage system or are available from third-party vendors. These typically include: creating volume snapshots (snapshots), creating a full working copy of a volume (snapclone), scheduled data replication (replication), and volume-level data mirroring to remote storage (synchronous/asynchronous mirroring).

Manufacturers of data storage systems (DSS) and storage software offer several concepts for solving this problem. This functionality can be present in the form of controller microcode (Hitachi), as an additional server module (appliance) (EMC, HP, IBM), or at the FC switch level (Cisco, Troika).

The manufacturers of Brand A data warehouses listed above zealously make sure that this functionality only works between “their own” ones, i.e. members of the same family of models. At the same time, solutions available from Cisco and Troika make virtualization transparent for any storage and are universal. However, it should be noted that both approaches are very cheap to implement and are not available to every organization.

You should also dwell on the features of choosing programs for performing archiving procedures. As with backup software, the choice of archiving software is determined by the individual needs and requirements of the business. Selection and implementation are carried out taking into account the business processes affected and the relevant legal requirements. An important point is the correct approach to the archived data sets, since often the application or type of information being archived determines the required software. The following most important selection criteria are generally recognized:
- taking into account legal aspects and legislative requirements;
- a full-fledged search system for the information array;
- ability to work with the required application;
- performance during archiving, searching and evaluation;
- support for necessary devices;
- integration into a complete storage solution.

Since most archiving software is application specific, some companies offer specialized solutions for classic email and ERP systems. Major manufacturers of systems for SAP include Open Text (SAP Document Access and SAP Archiving applications), IBM (DB2 CommonStore for SAP), EMC (Archive Services for SAP), Technoserv AS (Technoserv Content Server) and some others with their products for content and document management, and archiving. Integrated solutions that support archiving and information lifecycle management of structured and unstructured data from various applications will become the most rational option in the future, as they can reduce administration costs. HP Reference Information Storage System (RISS) supports today Microsoft Exchange and Outlook, Lotus Domino and documents in file formats of MS Office applications, Adobe PDF, HTML, etc.

The future evolution of backup and archiving software is driven by the trend of device virtualization, which will enable flexible resource sharing, broader and more comprehensive application support, and the development of high-performance search capabilities. In addition, a number of developments are aimed at improving compatibility between backup and archiving software, such as shared media management. In the long term, the boundaries will become even more blurred - perhaps both storage disciplines separately will cease to exist.

What do users of modern information systems fear most? We will not conduct surveys and, based on them, compile a list of nightmares that torment them. We are simply stating that high on this grim list is the threat of data loss. And if the loss of data on a home computer in most cases is annoying, then the loss of information on a corporate network can be fatal for both the employee and the company as a whole. But for the one responsible for the backup, the fatality of this loss is absolutely inevitable. However, how fair is this?

Modern information systems give priority to the problem of backup. Companies spend huge amounts of money on purchasing fault-tolerant disk arrays, specialized backup and storage devices, hire highly qualified professionals to maintain them - and still continue to lose data. Naturally, heads roll. However, the problem often lies in the misuse of perfectly debugged and configured systems. Figuratively speaking, users try to hammer nails with a microscope.

In February of this year, a terrible thing happened at a large publishing holding: data from one of the projects was lost. The following oddities were noted:

1. The project folder structure remained unchanged - only the files were missing.

2. No files were found on the backup tape (which, by the way, was performed daily), although the folder structure was fully present.

	Necessary measures to create a backup system A backup system is one of the necessary conditions for ensuring business continuity. According to Gartner, 43% of companies affected by disasters and experiencing a major permanent loss of corporate data were unable to continue operations. In order for the backup system to meet its purpose and operate optimally, it is necessary to complete a full cycle of design work, which, however, is recommended to be done for any system being created. The full cycle of work aimed at creating or upgrading a backup system usually includes the following stages: Technical audit of the computer system for the creation or modernization of a backup system; Development of the concept of a backup system - development of recommendations for the construction, modernization and development of a backup system. This type of work is not mandatory, but is recommended for large, dynamically developing systems; Design of a backup system - development of technical and working documentation; Development of a schedule for the transition from the old backup system to the new one. This type of work is necessary when upgrading the backup system, which has led to a significant change existing system; Supply and configuration of equipment and software; Development of operating procedures - organization of operating processes for the backup system, development of regulations and schedules for the backup system. This type of work is very important: without a properly organized operation process, not a single system, including the backup system, will work effectively; Drawing up a training program for customer personnel on data backup and recovery. For a backup system, personnel training plays a special role. Since the purpose of the backup system is to restore data after failures, the personnel carrying out this procedure will work in an emergency situation and lack of time to restore the system's functionality. Consequently, the execution of data recovery operations should be brought to automaticity by administrators, which can only be achieved through regular practice.

The investigation, traditionally for Russia, went in two directions: identifying those responsible and taking measures to eliminate the possibility of a similar situation repeating in the future.

First of all, complaints were made about the backup software. The reason why this was done turned out to be very prosaic: it is the backup software that must pass through the entire disk structure to copy information to tape, and therefore, in the event of any malfunction, it is theoretically capable of destroying files. Since this assumption came from the victims, simply stating that this was impossible was clearly not enough. Leaving aside the possibility of such a unique glitch occurring in a certified and legally purchased software product, we were forced to find a simple and clear way to convince non-specialists of the absurdity of this assumption. This task is extremely difficult (and in most cases impossible), but we succeeded. The fact is that the backup software uses one of the domain accounts when working with files; therefore, it is limited in its destructive capabilities by the rights of the account being used. By default, the local administrator account is used, which allows full access to all information stored on the server. On the one hand, this approach is justified by the fact that it eliminates the situation when backup cannot be performed due to lack of access rights to the backup information. On the other hand, administrator rights imply full access, allowing you to delete information. In the situation under consideration, the backup software worked under a specially created account that had access to all information, but without the ability to change it (read-only access). It was this fact that allowed the IT department to prove that the backup software was not involved in the incident.

Thus, after the cessation of the panic that arose, an attempt was made to comprehend what had happened and find its most acceptable explanation. First of all, it was established that three months before the moment in question, the lost project folder was empty. This fact was reflected in the backup software operation protocols and was included in the case. It was then determined that the server contained a completed project that had not been accessed for at least three months. As a result, after information was deleted from the server, it was stored on tapes for a month (the period of rotation of magnetic media in the backup scheme used), after which the tapes were overwritten, and this information was finally lost.

	Backup system requirements Since any modern information system is built on the basis of a network, the backup system must also be network-based, that is, ensure the preservation of data coming from all network nodes. In general, the following functional requirements are put forward for a network backup system: Building a system based on the “client-server” principle. When applied to backup, the client-server terminology means the following: the component of the backup system that manages all processes and devices is called the server, and the component responsible for saving or restoring specific data is called the client. In particular, such a system should provide: Management of backups throughout the entire network from dedicated computers; Remote backup of data contained on servers and workstations; Centralized use of backup devices. Multiplatform. The modern information network is heterogeneous. Accordingly, the backup system must fully function in such a network, that is, it is assumed that its server part will work in various operating environments and support clients on a variety of hardware and software platforms. Automation of typical operations. The backup process inevitably involves many cycles of different operations. For example, copying can occur every day at a certain time. Another example of a cycle is the process of overwriting information on backup media. If the daily backup is to be kept for a week, then after this period the corresponding media can be used again. This process of sequentially replacing backup media is called rotation. Cyclic work also includes preventive maintenance of backup devices, for example, cleaning the components of the tape drive mechanism of the tape drive using a special cassette after a certain period of operation. Thus, the backup system should perform cyclic work automatically and minimize the number of manual operations. In particular, it must support: Perform scheduled backups; Media rotation; Scheduled maintenance of backup devices. It should be noted that automation of work is one of the key conditions for reducing the cost of maintaining a backup system. Support various backup modes. Let's say that every day you need to back up a certain set of files, such as those contained in the same directory. As a rule, changes are made only to individual files during the working day, as a result of which daily copying of information that has remained unchanged since the previous backup was created is unnecessary. Based on this, the system must provide various backup modes, that is, support the ability to save only the information that has been changed since the creation of the previous copy. Quick recovery of network servers after a disaster. A network server can fail for various reasons, for example due to a system hard drive failure or due to software errors that lead to the destruction of system information. In this case, restoring it requires reinstalling the OS, configuring devices, installing applications, restoring the file system and user accounts. All these operations are very labor-intensive, and errors may occur at any stage of this process. Thus, to restore a server, it is necessary to have a backup copy of all information stored on it, including system data, in order to bring it back to working condition as quickly as possible. Data backup in interactive (on-line) mode. Often, an information system includes various client-server applications that must function around the clock. An example of this are postal systems, collaboration systems (for example, Lotus Notes) and SQL servers. It is impossible to back up the databases of such systems using conventional means, since they are open all the time. Therefore, they often have their own backup tools built in, but their use, as a rule, does not fit into the overall technology adopted by the organization. Based on this, the backup system must ensure that client-server application databases are saved online. Advanced monitoring and management tools. To manage backup processes and monitor their status, the backup system must have graphical monitoring and control tools and a wide range of event notification tools.

So, we have established the chronology of information loss. Now we are faced with a very difficult task - to identify those responsible. On the one hand, the backup system failed to cope with the task of saving information. On the other hand, this information was stored on tapes for a month and could be restored at the user’s first request. But this demand was not received, because the project was completed and no one was working with it. As a result, everyone is right, there are no guilty people, and there is no information. The situation - good example misuse of the right technology. Let's answer the question: what is the task facing backup systems? The priority task is to quickly and completely restore information in the event of a failure. Another thing is that in the example under consideration, the fact of the failure was not tracked - and, accordingly, data recovery was not performed. But this cannot in any way be blamed on the administration and backup service.

The situation under consideration is an example that clearly demonstrates the need to maintain at least a two-level backup system - daily backup of current information and separate backup of rarely used information (in our case, completed projects). Unfortunately, the need for such an approach to the problem of information security, as a rule, does not find understanding among management.

How did this sad story end? Here's what:

1. It was decided to save completed projects on DVD.

2. The rotation period of magnetic media has been increased to three months.

3. A policy for storing and reserving information was developed and adopted throughout the holding.

P.S. The data was nevertheless found in one of the file deposits, of which there are many on any network.

The book is intended for readers who are familiar with computer systems and the information technology industry and who want to expand their knowledge of storage systems and Windows NT architecture directly related to similar systems. The book covers enterprise storage systems, while paying less attention to consumer-grade systems. This publication seeks to support the interests of software professionals new to storage technologies and storage professionals seeking additional knowledge of the Windows NT storage architecture. At the same time, the book will be of interest to all readers who intend to obtain comprehensive information on the described topic.

Book:

Sections on this page:

There are various backup schemes that are used, for example, in a data storage center. It's worth noting that different backup categories can be used together. Backup is classified as follows:

based on architecture;

based on functionality;

based on network infrastructure.

Let's look at each type of classification in more detail.

5.3.1 Backup classification based on architecture

One type of backup classification is based on architecture. A backup depends on the objects it is applied to and how well the backup application supports those objects. The available backup architectural types are described in Sections 5.3.1.1 through 5.3.1.3.

5.3.1.1 Backup at the disk image and logical block level

In this case, the backup application works with blocks of data. Typically, such a backup scheme requires that all applications on the server have no access to the copied data. The application accesses the hard drive regardless of its internal structure, and then performs read/write operations at the logical block level.>

The advantage of this type of backup is the speed of data backup and recovery operations, which is especially important for restoring data after critical system failures. The disadvantage is that there is a ban on access to the disk by applications and even operating system. Another disadvantage is that an excessive number of unused logical blocks are copied from the backup when backing up a disk with allowed files. Some backup applications provide the appropriate software logic needed to detect and skip unused logical blocks. These backups are called sparse copies disk image.

Finally, it is quite difficult to retrieve only a specific file or a few files, as opposed to recovering all the data on the disk. To do this, the backup software must process the file system metadata stored on the tape and calculate the location of the required file on the tape. Some programs allow you to restore certain files from an image-level backup, but only for some operating systems. Other applications try to optimize file recovery from an image-level backup by writing file metadata to tape, such as a file location table for the FAT16 file system.

The version of NTFS that comes with Windows 2000 already contains all the metadata in the files, such as a bitmap that corresponds to the location of logical blocks. The data recovery program finds the necessary metadata, from which it calculates the location on the magnetic tape of each necessary logical block of the required file. After this, the tape is scrolled in one direction and all the necessary sections are read during the rewinding process, which allows you to obtain all the data for file recovery. The tape does not rewind in both directions, so not only the recovery time is reduced, but also the life of the tape. The backup applications described include, for example, the Legato Celestra program.

Please note that sometimes the choice of backup method is limited. If the database uses a bare disk volume without a file system, then the only choice is between an image-level backup and an application-level backup (this type of backup is discussed in Section 5.3.1.3).

5.3.1.2 File-level backup

In this type of backup, the backup program uses the services of the operating system and the file system. One advantage is the efficiency of recovering a specific file or set of files. Another advantage is that files can be accessed simultaneously by the operating system and applications when backing up.

However, this was not without its drawbacks. Backups take longer, especially compared to image-level backups. If you are copying a large number of small files, the load on the operating system and file system when accessing directory metadata can be significant. Moreover, there is a problem open files, which was described earlier.

Another drawback is related to security. This issue occurs regardless of the backup method (image or file level) and occurs when the backup is performed under the rights account administrator or backup operator, not the user. This is the only way to recover files from multiple users in a single restore operation. A prerequisite is that file metadata, such as access control lists and file ownership information, are correctly configured. Solving the problem requires support from the file and operating system APIs, which is necessary to configure metadata when restoring data from a backup. In addition, the backup and recovery application must correctly use the provided capabilities.

5.3.1.3 Application level backup

In this case, data backup and recovery is performed at the application level, such as Microsoft SQL Server or Microsoft Exchange. Backup is performed using an API provided by the application. In this case, a backup consists of a set of files and objects that form the state of the system at a certain point in time. The main problem is that backup and restore operations are tightly coupled to the application. If the API or functionality of an existing API changes with the release of a new application, the administrator will have to migrate to the new version of the backup program.

Applications use a blank disk without a file system or write a huge file to it that contains the application's own metadata. An example of such an application is Microsoft Exchange. Windows XP and Windows Server 2003 support important NTFS features that make it possible to recover such files. The file is restored in logical blocks and marked at the end new feature Win32 API, which is called SetFileValidData.

5.3.2 Backup classification based on functionality

Another method of classifying backup applications is based on the features provided during the backup process. Note that data storage centers typically use at least two, and most often all, of the backup types described below, namely full, differential, and incremental.

5.3.2.1 Full backup

At full backup(full backup) the complete set of files or objects, as well as their associated metadata, is copied to the backup media. The advantage is that only one set of recovery media is used in the event of a system failure. The disadvantage is the copying time, since all data is copied. Full backups are often performed at the disk image level or at the block level.

5.3.2.2 Differential backup

At differential backup(differential backup) are archived all changes that have occurred since the last full backup. Since differential backups can be created at the image level or at the file level, this change set will be the set of disk blocks that have changed (for an image-level backup) or the set of files that have changed (for a file-level backup). The main advantage of differential backup is the significant reduction in backup time compared to a full backup. On the other hand, recovery from a failure takes longer. Recovering from a failure will require two data recovery operations. The first will restore data from a full backup, and the second will restore data from a differential backup.

When using low-cost storage subsystems, differential file-level backup is used in cases where applications create many small files and change some of the files after taking a full backup. However, such backups do not apply if the hard drive is used by database management applications that constantly make small changes to huge database files. This way, a file-level backup will create a copy of the entire file. An example of such a program is Microsoft Exchange, which constantly strives to make small changes to huge database files.

With older storage subsystem models, image-level differential backup can be used in any situation, including backing up database application files. The reason for this efficiency is that it stores a large amount of metadata, which allows you to quickly identify disk blocks that have changed since the backup. This way, only disk blocks that have changed will be backed up, and large numbers of disk blocks that have not changed will not be backed up. Even though backup efficiency is higher when using older storage subsystems, there remains a need to use an API that allows you to start a backup at a certain point in time and continue data I/O after the backup is complete. The older storage model operates by reducing the amount of data I/O that must be stopped during backups.

5.3.2.3 Incremental backup

At incremental backup(incremental backup) are archived only changes since the last full or differential backup. Obviously, this type of backup requires less time because files that have not changed since the last full or incremental backup are not copied to the backup media. The disadvantage of this method is the length of the disaster recovery operation, since it is performed using a set of multiple media corresponding to the last full backup and several incremental backups.

In the absence of older storage subsystem models, incremental backups are performed when different sets of files are changed or added. When using older storage subsystem models, incremental block-based backups can be used because in this case, sufficient metadata is available to identify changed blocks.

5.3.3 Backup classification based on network infrastructure

One way to classify backups is based on network topology and its impact on choosing the best method for backing up connected nodes. Backup types depending on the network infrastructure (DAS, NAS, SAN backup, independent of local network and from the server) are discussed in sections 5.3.3.1–5.3.3.4.

5.3.3.1 DAS redundancy

This oldest form of backup originated in the days when storage devices were connected directly to the server. Despite the development of network-attached storage devices, DAS backup remains quite popular for copying data hosted on Windows servers. The DAS redundancy scheme is shown in Fig. 5.3. / The advantage of DAS redundancy is its ease of use. The application on the server reads data from the corresponding disk volume and writes it to magnetic tape. However, DAS redundancy has several disadvantages.

Using multiple tape drives (one for each server needing backup), which requires significant financial investment. In other words, sharing a single drive across multiple servers is nearly impossible.

High total cost of ownership (TCO) because multiple tape drive backups require multiple administrators.

Storing multiple tapes can become confusing.

Because data on multiple servers is often duplicated but not synchronized, the same data is transferred to tape, so storing similar data on multiple tapes can become confusing.

Rice. 5.3. DAS reservation

Last, but not least, the server must handle read/write requests for data between the disk and the tape drive.

5.3.3.2 NAS backup

As noted in Chapter 3, the era of DAS storage ended with the advent of client/server systems, when clients and servers began sharing local network resources. This allowed for an architecture in which a tape drive connected to a server was accessed by multiple network servers.

In Fig. Figure 5.4 shows a typical NAS backup scenario. The left pane of the diagram shows several servers. These could be application servers or file and print servers. The right pane contains the backup server and its attached tape drive. This drive can be used to back up information from multiple application servers, file servers, and print servers. Thus, NAS redundancy allows you to share tape storage to back up data across multiple servers, resulting in lower overall costs.

NAS redundancy has some disadvantages.

The backup operation impacts LAN throughput, which often requires LAN segmentation to redirect backup streams to a separate network segment.

The operating time of nodes increases. In other words, the time during which servers must be available to service user requests and transactions increases. In addition, the amount of data stored on the server increases, which requires more time to back up this data.

Rice. 5.4. NAS redundancy scheme

Considering the relevance of the problems described, ensuring backup efficiency becomes the only criterion when designing networks and determining the exact number of required backup devices.

5.3.3.3 SAN redundancy

The development of storage area networks has led to the emergence of new backup concepts. The new capabilities are based on the fact that a storage area network can provide sufficient bandwidth between any two devices and, depending on the topology, can provide simultaneous low-latency communications between multiple pairs of devices. On the other hand, using a Fiber Channel ring topology with more than 30 devices does not provide the ability to create multiple high-bandwidth, low-latency connections, since the total ring bandwidth will be shared among all connected devices.

In Fig. Figure 5.5 shows the architecture of a typical SAN backup application. Note the Fiber Channel bridge. Most tape drives do not support Fiber Channel (they use parallel SCSI), so you will need a bridge to connect such devices. In Fig. 5.5 Windows NT servers are connected simultaneously to a local network and a storage network.

The backup topology (see Figure 5.5) has a number of advantages.

The tape drive may be located quite far from the server whose data is being backed up. Such drives are usually equipped with a SCSI interface, although recently drives with a Fiber Channel interface are increasingly appearing. This means that they can only be connected to one SCSI bus, making it difficult to share the drive among multiple servers. Fiber Channel-based SANs provide multi-device support to solve sharing problems. Note that this still requires a method to ensure that the tape drive is accessed correctly using the appropriate permissions. Examples of such methods are presented below.

Rice. 5.5. Backup via storage network

The zoning method allows one server to access the tape drive at a certain point in time. The challenge is ensuring that servers comply with zoning requirements. In addition, you must ensure that the tape changer or multi-cassette drive is used correctly.

The next method is to use SCSI interface commands such as Reserve And Release.

The method of connecting a tape drive to a server allows you to share access to the device through special server software. Sharing a tape drive is a very attractive solution because tape drives are quite expensive devices. The drives described include, for example, the Tivoli device from IBM.

Backup technology without a local network got its name because data transfer is performed outside the local network using SAN. This reduces the load on the local network, so applications do not suffer from reduced network throughput when backing up data.

Offline backup allows you to use resources more efficiently by sharing tape drives.

Backing up and restoring data without a local network is more error-resistant because backup can be performed by multiple devices simultaneously if one device fails. Likewise, multiple devices can be used during data recovery, allowing for more efficient resource planning.

Finally, backup and restore operations complete much faster because SANs provide faster data transfer rates.

5.3.3.4 Server-independent redundancy

This backup is sometimes called backup without server or even third party copying. Note that a server-independent backup is typically a LAN-agnostic backup, eliminating the need to move data from a specific host. The idea behind this backup method is to use the SCSI Extended Copy command.

Server-independent backup is an initiative of the SNIA association, which was implemented in the SCSI Extended Copy commands approved by the INCITS committee, or more precisely, the T10 technical subcommittee (ANSI document INCITS.351:2001, SCSI Primary Commands-2). Please note: the SCSI standard already described support for copy commands, but previously, using the commands required connecting all SCSI devices to the same bus (the Copy command has since been considered obsolete; more detailed information is provided on the Web site http: //www.110. org). The Extended Copy command adds additional capabilities such as using the source and destination of data across different SCSI buses. In this case, the addressing supported by the command syntax is fully preserved.

In a server-independent backup, the backup server can handle other requests while the data is being copied using the data movement agent. Data is transferred directly from the data source to the destination, namely the backup media (instead of copying from the source to the backup server and then transferring it to the backup media).

Rice. 5.6. Server-independent backup

While we understand the benefits of server-independent backup, we must not forget that data recovery is a completely different challenge. Server-independent restore operations remain extremely rare. Backups created using this technology are very often restored using traditional methods, which involve using a server with some kind of software to backup and restore the data.

The principle of server-independent backup is demonstrated in Fig. 5.6. To simplify the diagram, the figure shows the minimum number of components required to illustrate the backup. In practice, storage networks have a more complex structure. In Fig. 5.6 shows the server under Windows control, connected to a Fiber Channel switch using a Fiber Channel HBA. In addition, a Fiber Channel-K-SCSI router is used, to which the SCSI tape drive and disk devices are connected. Disk and tape devices do not have to be connected to the same router.

The media server application on the Windows server finds the data movement agent on the router using Plug and Play technology. The backup application defines additional information about the backup (disk device ID, starting logical block, amount of data being copied, etc.). The backup server software initially issues a sequence of commands to the tape drive to back up the device and mount the required media. Next, the backup server software sends the command Extended Sora to the data movement agent that runs on the router. The agent coordinates the transfer of the necessary data. Once the copy is complete, the agent returns the service information to the backup program running on the Windows server.

Several components play an important role in the server-independent backup process, including the data source and destination, the move agent, and the backup server.

Data source is a device that contains data that needs to be backed up. Typically, an entire volume or disk partition is backed up. The data source must be accessed directly by the data movement agent (discussed below). This means that storage devices attached to the server cannot be data sources for server-independent backups, since direct addressing outside the server is not possible.

Data destination Typically a magnetic tape drive onto which data is written. The device can be a disk if you are backing up to disk rather than tape. Tape devices are typically connected to a port on the fabric architecture to avoid damaging data transferred to the tape if other parts of the SAN fail. For example, if a tape drive is connected to a shared Fiber Channel ring, an error in the operation of another device or the connection or disconnection of a device from the ring can cause data to be written to stop and the ring to reinitialize, compromising the integrity of the data being written to the tape.

Data Movement Agent usually built into the router via firmware as it must handle the SCSI command Extended Sora, which is sent to the router as a Fiber Channel packet. Switches and hubs that process only the Fiber Channel frame header are not well suited to support DMA operation, but this may change in the future.

The data movement agent is activated after receiving instructions from the media server. Most tape drives connected to a SAN are SCSI devices. Therefore, a router that supports packet translation between Fiber Channel and SCSI interfaces is required. At the moment, tape drives with a Fiber Channel interface are increasingly appearing, and some companies, such as Exabyte, provide firmware for such drives that add data movement agent functions. Additionally, basic Fiber Channel tape drive libraries typically have built-in Fiber Channel-SCSI routers, allowing the library to use its own data movement agent. Note that the agent can be implemented in junior workstation or even server software. Crossroads, Pathlight (now ADIC), and Chaparral provide routers with data movement agents built into the firmware. A SAN can have multiple agents from multiple vendors, which does not prevent agents from coexisting on the same network.

Of course, in order for the data movement agent to be used, it must be found (using the SCSI command Report LUNs) and ensure proper addressing (via WWN) from the backup server. In addition, the agent can perform two backups simultaneously. For example, one copy session can be carried out to a geographically distant mirror resource, but for this the backup server must issue two commands.

The backup server is responsible for all commands and operation management. Let us list once again all the main responsibilities of the backup server.

The server software makes the tape drive accessible by using the appropriate SCSI commands Reserve And Release.

Mounting backup media.

Determining the exact address of the data source and the placement of data in logical blocks, as well as the amount of data to be backed up.

Having received all the necessary information, the server sends the command Extended Sorry to the data movement agent. The agent then sends a sequence of commands Read source of data and records information at the destination.

Computer Associates, CommVault, LEGATO, and VERITAS provide server-independent backup software. Suppliers of routers with server-independent backup capabilities continually work with software companies to make their products compatible. Case V that to support basic SCSI commands Extended Copy Manufacturers use different commands.

Please note that while server-independent backup technology is mature, vendor support for server-independent recovery is extremely limited.

5.3.3.5 Windows Server family of operating systems and server-independent backup

Numerous advertisements and marketing literature claim that a particular method of implementing server-independent backup technology is compatible with Windows 2000. Let's look at this concept in more detail. The following describes each of the four components that make up server-independent backup: source data, data destination, backup server software, and data movement agent.

In most cases, a data movement agent running outside of a Windows NT server cannot address data stored on a Windows NT server. HBAs connected to a Windows NT server typically act as initiators and do not respond to commands. Report LUNs. If the Windows NT server uses an off-site storage device, such as a RAID array connected to a Fiber Channel switch, then that device will be available to the move agent. Therefore, rather than stating that a storage device used by Windows NT cannot be the source of data for server-independent backup, it should be clarified that the source of data cannot be a storage device that is internal to the Windows NT server.

Using Windows NT internal storage as a data destination is also not possible, since the destination must also be available to the DMA for addressing.

Running the backup program on a Windows computer is a good option. The HBA connected to the Windows server may issue a sequence of commands Report LUNs to each device (LUN 0) that will be discovered. The backup program then looks at all visible devices and logical units to determine which ones can act as a third-party copy agent. Some programs report additional LUNs that are required when issuing commands Extended Sora. Many backup programs that use additional LUNs go through a device discovery process to test the DMA functionality.

The Intermediate SCSI Interface (IOCTL) on Windows NT can be used to transmit command Extended Sora to the data movement agent (the command is sent from a backup server running Windows NT). The Windows NT operating system does not have built-in support for move agents; Plug dnd Play technology allows you to detect the agent, but additional drivers are required to register the latter in the system registry.

The final question remains: can you run the Data Move Agent software on a server or workstation running Windows NT? One advantage of this solution is that the move agent will be able to address and access storage devices visible to the Windows server. But a backup server located outside of Windows NT will not be able to discover storage devices attached to a computer running a data movement agent. The agent must be able to act as an initiator and target for SCSI commands. Because the HBA connected to a computer running Windows NT rarely acts as a target device, the Extended Copy command may not reach the Data Mover.

Please note: on Windows NT, applications use an intermediate interface to issue SCSI commands (DeviceloControl with parameter IoControlCode equal IOCTOL_SCSI_PASS__THROUGH or IOCTL_SCSI_PASS_THROUGH_DIRECT).

Send your good work in the knowledge base is simple. Use the form below

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

Posted on http://www.allbest.ru/

1. Statement of the problem

2. Introduction

3. Backup technologies

3.1 Overview of backup technologies

3.2.2 Disk drives

3.2.3 Network technologies

3.3. Backup storage

4.1 GFI Backup overview

4.1.1 General characteristics

4.1.2 Practical use

4.2.1 General characteristics

4.3 Acronis True Image overview

4.3.1 General characteristics

5. Application and comparison of the reviewed software products

6. Conclusion

7. List of references used

1. Statement of the problem

Task 3.5 "Tasks and means of data backup and storage." Learn the basic tasks and methods of data backup and storage. Review and Compare software well-known manufacturers (Microsoft, Veritas, Symantec, etc.). Write a description practical application available means.

2. Introduction

Backup is the process of creating a coherent (consistent) copy of data. Backup is becoming increasingly important as data volumes increase significantly in the computer industry. The backup subsystem is a very important part of any information system. When properly organized, it can solve two problems at once. Firstly, reliably protect the entire range of important data from loss. Secondly, to organize a quick migration from one PC to another if necessary, that is, to actually ensure uninterrupted work for office employees. Only in this case can we talk about efficient work Reserve copy. Mastering backup tactics is an essential attribute of professionalism for the user and system administrator. It follows from the user’s decision for himself, by what methods and at what level the information will be stored (the required software and hardware depends on this), the volume of information necessary for saving (the selected information media depends on this), the size and structure of the local network (this determines depends on the actual mechanism for systematically performing copying).

To perform the backup procedure, special hardware and software subsystems called backup subsystems are usually created. They are designed specifically for both regular automatic copying of system and user data, and for rapid data recovery. Storing information separately from system files is already a mandatory rule. For the average user, this means, at a minimum, dividing the HDD into three logical drives: for the system, for applications, for data. In the case of a corporate employee with a large amount of confidential information, placing the information on other, non-system physical disks. This measure also facilitates the data archiving operation itself. The principle of separate storage of information applies to both file archives and disk images. They must also be stored at least on non-system partitions of one HDD. In the case of a corporate user, the principle of separate storage of information should be implemented even more strictly: at least one of the copies should be stored in a separate place so as not to lose corporate information in case of unforeseen circumstances.

3.Backup technologies

3.. Overview of backup technologies

Depending on the importance of the information stored on the computer and the frequency of its use, several types of data backup are performed:

Full backup.

Differential backup.

Incremental backup.

3.1.1 Full backup

It is the main and fundamental method of creating backup copies, in which the selected data array is copied entirely. This is the most complete and reliable type of backup, although it is the most expensive. If it is necessary to save several copies of data, the total stored volume will increase in proportion to their number. To prevent a large amount of resources used, compression algorithms are used, as well as a combination of this method with other types of backup: incremental or differential. And, of course, a full backup is indispensable when you need to prepare a backup copy for quickly restoring the system from scratch.

Advantages of the method:

Easily search for files - Because everything on your device is backed up, you don't have to browse through multiple media to find the file you need.

A current backup of your entire system is always located on a single media or set of media - If you need to restore your entire system, you can find all the information you need in the latest full backup.

Disadvantages of the method:

Redundant data protection - since most system files change rarely, each subsequent full backup is a copy of the data saved during the first full backup. A full backup requires a large amount of storage space.

Full backups take longer - Full backups can take a long time to complete, especially if you select devices on the network for storage.

3.1.2 Differential backup

It differs from incremental in that data is copied from the last moment of Full backup. The data is stored in the archive on a “cumulative basis”. On Windows family systems, this effect is achieved by the fact that the archive bit is not reset during differential copying, so the changed data ends up in the archive copy until a full copy resets the archive bits. Due to the fact that each new copy created in this way contains data from previous, this is more convenient for completely restoring data at the time of the accident. To do this, you only need two copies: the full one and the last of the differential ones, so you can bring data back to life much faster than gradually rolling out all the increments. In addition, this type of copying is free from the above-mentioned features of incremental copying, when, with a complete recovery, old files are reborn from the ashes. There is less confusion. But differential copying is significantly inferior to incremental copying in saving the required space. Since each new copy stores data from previous ones, the total volume of reserved data can be comparable to a full copy. And, of course, when planning the schedule (and calculating whether the backup process will fit into the time “window”) you need to take into account the time to create the last, largest, differential copy.

Advantages of the method:

Easily search files - To restore a system protected with a differential backup strategy, two backups are required - the latest full backup and the latest differential backup. Recovery time is significantly faster than backup strategies that require the last full backup and all incremental backups created since the last full backup.

Faster backup and recovery times - Differential backups take less time than full backups. Disaster recovery is faster because only the latest full backup and differential backup are needed to completely restore the device.

Disadvantage of the method:

Redundant data protection - All files changed since the last incremental backup are preserved. This creates redundant backups.

3.1.3 Incremental backup

Unlike a full backup, in this case not all data (files, sectors, etc.) are copied, but only those that have changed since the last copy. Various methods can be used to determine the backup time, for example, on systems running Windows operating systems, a corresponding file attribute (archive bit) is used, which is set when the file has been modified and reset by the backup program. Other systems may use the date the file was modified. It is clear that a scheme using this type of backup will be incomplete if a full backup is not carried out from time to time. When performing a full system restore, you need to restore from the last copy created by Full backup, and then one by one restore data from incremental copies in the order in which they were created. This type is used to reduce the amount of space consumed on information storage devices when creating archival copies (for example, reduce the number of tape media used). This will also minimize the time it takes to complete backup jobs, which can be extremely important when the machine is constantly running or when pumping large amounts of information. Incremental copying has one caveat: step-by-step recovery also returns the necessary deleted files during the recovery period. For example: let’s say a full backup is performed on weekends, and an incremental one on weekdays. The user created a file on Monday, changed it on Tuesday, renamed it on Wednesday, and deleted it on Thursday. So, with a sequential, step-by-step data recovery for a weekly period, we will receive two files: with the old name on Tuesday before the renaming, and with a new name created on Wednesday. This happened because different incremental copies stored different versions the same file, and eventually all variants will be restored. Therefore, when sequentially restoring data from an “as is” archive, it makes sense to reserve more disk space so that deleted files can also fit.

Advantages of the method:

Efficient use of media - Because only files that have changed since the last full or incremental backup are saved, backups take up less space.

Faster backup and recovery time - Incremental backups take less time than full and differential backups.

Disadvantage of the method:

Backup data is stored on multiple media - Because backups are located on multiple media, it may take longer to restore your device after a disaster. Additionally, to effectively restore the system, the media must be processed in the correct order.

3.2 Technologies for storing backups and data

In the process of backing up data, the problem of choosing a technology for storing backup copies and data arises. Currently, the following types of media are especially popular:

Magnetic tape drives.

Disk drives.

Network technologies.

3.2.1 Tape drives

Not only large corporations, but also small businesses are well aware of the need to backup and restore information. In enterprise-scale systems and networks of large departments, in small companies and individual users, streaming drives, or streamers, are equally successful. Their design is based on a tape drive mechanism operating in inertial mode. Magnetic tape drives have been used together with computers since the early 50s - it was then that they began to replace “paper” storage media - punched tapes and punched cards. An important factor that ensures such long-term interest in magnetic tape drives is the low cost of storing information. The main problem with using tape drives today is that many of them use incompatible tape formats. This often makes it difficult not only to select a specific drive, but also to exchange data during its operation. A lot of efforts have been made to solve this problem, but in general it can be stated that fundamental changes have not yet occurred (although there is some progress in this direction). The most widely used technologies today are Travan, DLT (Digital Linear Type), DAT-DDS ( Digital Audio Tape-Digital Data Storage), LTO (Linear Tape Open), Mammoth and AIT (Advanced Intelligent Tape). To make an informed choice of a backup system, you need to clearly understand the advantages and disadvantages of different devices, which are largely determined by the capacity of the system, its speed, reliability and price. The main drivers for improving the performance of mid-range and high-end tape devices are the widespread use of the Internet and the proliferation of corporate intranets, the increase in the number of servers (needed to support the growth of these networks), and the tightening requirements for information storage and its recovery in the event of disasters. The demand for backup and storage systems is particularly driven by the increasing use of applications such as multimedia, video on demand, audio content, image processing, etc. Two methods of recording on magnetic tape are used: slant and linear serpentine. In oblique recording systems, multiple read/write heads are placed on a rotating drum mounted at an angle to a vertical axis (a similar arrangement is used in consumer video equipment). The movement of the tape when writing/reading is possible only in one direction. In linear serpentine recording systems, the read/write head is stationary when the tape moves. Data on tape is recorded in the form of many parallel tracks (serpentine). The head is placed on a special stand; When the end of the tape is reached, it moves to another track. The tape moves when writing/reading in both directions. In fact, several such heads are usually installed so that they serve several tracks at once (they form several write/read channels).

Pros of storing data on tape:

Low cost.

Low power consumption of the drive.

Large volumes of data.

An easy way to increase the amount of data you store without making a significant investment.

Disadvantages of storing data on tape:

Low data access speed.

The complex process of processing parallel data queries.

3.2.2 Disk drives

There are two most common types of disk drives: magnetic hard drives and optical drives.

Hard disk drives (Hard Disk Drive, HDD) are the main devices for operational storage of information. Modern single drives are characterized by volumes from hundreds of megabytes to several gigabytes with access times of 5-15 ms and data transfer rates of 1-10 MB/s. Regarding the server case, a distinction is made between internal and external drives. Internal drives are significantly cheaper, but their maximum number is limited by the number of free compartments in the case, the power and the number of corresponding connectors of the server power supply. Installing and replacing conventional internal drives requires shutting down the server, which is unacceptable in some cases. Internal drives with the possibility of “hot swap” (Hot Swap) are ordinary hard drives installed in special cassettes with connectors. Cassettes are usually inserted into special compartments on the side of the front panel of the case; the design allows the drives to be removed and inserted while the server is powered on. For standard cases, there are inexpensive devices (Mobile Rack) that provide quick removal of standard hard drives. External drives have their own cases and power supplies; their maximum number is determined by the capabilities of the interface. Maintenance of external drives can also be performed while the server is running, although it may require stopping access to some of the server’s drives.

For large volumes of stored data, external storage units are used - disk arrays and racks, which are complex devices with their own intelligent controllers that, in addition to normal operating modes, provide diagnostics and testing of their drives. More complex and reliable storage devices are RAID arrays (Redundant Array of Inexpensive Disks - a redundant array of inexpensive disks). For the user, RAID is a single (usually SCSI) disk in which simultaneous distributed redundant writing (reading) of data is performed on several physical drives (typically 4-5) according to rules determined by the implementation level (0-10). For example, RAID Level 5 allows you to correct errors during reading and replace any disk without stopping data access.

CD-ROM drives extend the capabilities of NetWare storage systems. Existing drives provide read speeds from 150 kB/s to 300/600/900/1500 Kbyte/s for 2-, 4-, 6- and 10-speed models with an access time of 200-500 ms. NetWare allows you to mount a CD as a network volume that can be read by users. The volume capacity can reach 682 MB (780 MB for Mode 2). CD-ROM devices are available with various interfaces, both specific (Sony, Panasonic, Mitsumi) and general ones: IDE and SCSI. The NetWare server only supports CD-ROMs with SCSI interfaces; new drivers also exist for the IDE; devices with specific interfaces can only be used in DOS for system installation. From a performance point of view, it is preferable to use CD-ROM SCSI, but they are significantly more expensive than similar IDE devices. On a server with SCSI disks, using a CD-ROM with an IDE interface may not be possible due to adapter conflicts.

The advantages of such drives are:

Quick access to data.

Possibility of parallel access to data without significant loss of speed.

Disadvantages of disk drives:

Higher cost than tapes.

Higher power consumption.

More expensive storage expansion.

Inability to ensure high security of copies.

3.2.3 Network technologies

Network-attached storage is built on three fundamental components: switching, storage, and files. All storage products can be represented as a combination of the functions of these components. This can be confusing at first: because storage products were developed in completely different directions, features often overlap.

The network runs many client-server applications and various types of distributed applications, but storage is a unique and specialized type of application that can function across multiple network environments. Since storage processes are tightly integrated with networks, it is appropriate to recall that network storage is a system application. The services provided by network storage applications can be used by complex enterprise programs and consumer applications. As with many technologies, certain types of systems are better suited to the demands of complex, high-level applications.

The term switching applies to all software, hardware, and services that transport and manage storage on network-attached storage. This includes various elements such as cabling, network I/O controllers, switches, hubs, address fetching hardware, data link control, transport protocols, security, and resource reserves. SCSI and ATA data bus technologies are still widely used in networked storage and are likely to continue to be used for a long time. In fact, SCSI and ATA products are used much more frequently in NAS technology today. There are two important differences between SAN storage networks and regular LANs. Storage area networks (SANs) automatically synchronize data between separate systems and storage locations. Network storage requires high-fidelity components to provide a reliable and predictable environment. Despite its distance limitations, parallel SCSI is an extremely reliable and predictable technology. If new switching technologies such as Fiber Channel, Ethernet, and InfiniBand replace SCSI, they will need to demonstrate equal or better levels of reliability and predictability. There is also a point of view that considers switching as a storage channel. The very term “channel”, which originates in the environment of large computers, implies high reliability and performance.

Storage primarily affects address space block operations, including virtual environment creation where logical storage block addresses are mapped from one address space to another. Generally speaking, the storage functionality of network attached storage hasn't changed much, except for two notable differences. The first is the ability to find device virtualization technologies, such as device management within network storage equipment. This type of feature is sometimes called storage domain controller or LUN virtualization. The second major differentiator for storage is scalability. Storage products, such as storage subsystems, have significantly more controllers/interfaces than previous generations of bus technology, as well as much larger storage capacity.

The file organization function presents an abstract object to the end user and applications, and organizes the layout of data on real or virtual storage devices. The bulk of the functionality of files in network storage is provided by file systems and databases; they are complemented by storage management applications such as backup operations, which are also file applications. Network storage has made little difference to file functions to date, with the exception of the development of NAS file systems, particularly Network Appliance's WAFL file system. In addition to the mentioned NAS and SAN storage technologies, aimed at large and wide area networks, in small local networks the dominant position is occupied by DAS technology, according to which the storage is located inside a server that provides the storage volume and the necessary computing power.

The simplest example of a DAS would be a hard disk drive inside a personal computer or a tape drive connected to a single server. I/O requests (also called commands or data transfer protocols) directly access these devices. However, such systems do not scale well, and companies are forced to purchase additional servers to expand storage capacity. This architecture is very expensive and can only be used to create small data warehouses.

3.3 Backup storage

When backups are made, these copies must be retained. However, it is not at all so obvious what exactly should be stored and where. To correctly determine where to store copies, you must first consider the circumstances under which the backups will be used. Three main situations can be distinguished:

Recovery separate files at the request of users.

Global emergency recovery.

Archive storage will likely never be needed.

Unfortunately, there are incompatible contradictions between the first and second situations. When a user deletes a file by accident, he wants to get it back immediately. Therefore, the backup media should be no more than a few meters away from the computer on which the data is to be restored. In the event of an emergency, you will need to perform a full recovery of one or more computers in your data center, and if the failure occurs is physical, it will destroy not only the computers, but also all backups stored nearby. Archive storage is less controversial - the likelihood that an administrator will use it is quite low, so if the backup media is stored far away from the data center, this should not be a problem. Different approaches may be chosen to address these different challenges, depending on the needs of the organization. The first possible approach is to store several days' worth of copies on site, and then move those copies to more secure off-site storage when new daily copies are created. Another approach is to support two media sets:

A collection of media in a data center used solely for on-demand recovery of individual data

A set of media for remote storage and recovery in case of emergencies

Of course, having two sets means having to back everything up twice or copy it. It can be done, but double backups can take a long time, and copying backups may require multiple devices to handle the backups (and perhaps dedicate a separate computer to copying. The challenge for a system administrator is striking a balance between meeting the needs of users and availability of backup copies in case of worst-case scenarios.

3.4 Restoring data from backups

In most cases, backups are performed daily, and restores tend to occur less frequently. However, recovery is inevitable, there will definitely be a need for it, so it is better to prepare for it. Here it is important to analyze two important situations that arise when restoring data from backups:

Recovering data on a clean computer.

Checking the relevance of backups.

3.4.1 Restoring data on a clean computer

Blank computer data recovery is the process of restoring a complete copy of the system on a computer that has absolutely no data - no operating system, no applications, nothing. In general, there are two main approaches to recovery on a bare computer:

Reinstallation followed by recovery, here the base operating system is installed in the same way as on a completely new computer. Once the operating system is installed and properly configured, the remaining drives can be connected and formatted, and all copies can be restored from backup media.

A system recovery disk is some kind of bootable media (usually a CD-ROM) that contains a minimal system environment and allows you to perform most basic administrative tasks. The recovery environment contains the necessary utilities for partitioning and formatting disks, the device drivers needed to access the backup device, and the programs needed to restore data from backup media.

3.4.2 Checking the relevance of backups

All types of copies should be reviewed periodically to ensure that the copies can be read and are current. Indeed, sometimes copies, for one reason or another, may not be readable; most often this is discovered only when data is lost, when a backup copy is required. The reasons for this can be very different, for example: the tape drive head is misaligned, an incorrectly configured backup program and operator error. But whatever the reason, without periodic checks, the administrator cannot be sure that there really are backups from which data can be restored someday later.

4. Types of backup programs

Today, there are many software products to provide data backup technology. At the corporate level, products such as:

Acronis True Image Home.

Paragon Drive Backup Server Edition.

Symantec Backup Exec.

Windows System Recovery.

For network backup:

Paragon Drive Backup Enterprise Server Edition.

Acronis Backup & Recovery.

A further review of backup technologies will be based on a description of the practical use of the following three software products:

Paragon Drive backup Workstation.

Acronis True Image Home.

4.1 GFI backup program overview

4.1.1 General characteristics.

System requirements:

Microsoft Windows 7 (x86 or x64), Server 2008

(x86 or x64), Vista (x86 or x64), Server 2003 Standard/Enterprise

(x86 or x64), XP (x86 or x64)

Processor - Intel Pentium 4 or similar

Memory - 512 MB

Physical memory - 100 MB for installation

Characteristics:

1.Secure and reliable data backup and recovery.

GFI backup provides centralized management of backup and recovery as information loss protection, preventing the loss of data such as spreadsheets, projects and images. This process involves creating a backup from the source to a selected location.

2. Data synchronization.

File synchronization is the process of maintaining a current set of files across multiple locations, such as a workstation and laptop. If a user adds, deletes or modifies a file in one location, GFI Backup adds, deletes or modifies the same file in all other locations. Using the GFI Backup Agent, users can create their own synchronization tasks in addition to centralized backup operations.

3. Backup to any data storage device; backup via FTP.

GFI Backup allows you to back up to internal and external hard drives, local network drives, network attached storage devices, media

CD/DVD/Bluray, portable devices (USB devices, memory cards, flash memory, floppy disks, etc.), and to remote locations using FTP with automatic renewal system.

6. Using standard Zip archives.

Unlike other backup programs, GFI Backup does not use its own archive formats, but uses the standard Zip format. This allows

restore data manually even if GFI Backup is not installed. You can choose to create self-extracting archives, as well as backup without data compression for speed and redundancy. When using Zip archives, GFI Backup is able to split and save files onto multiple media.

4.1.2 Practical use of the program

In order to evaluate the capabilities of the program, we will need:

1. Personal computer with an installed operating system and a set of necessary user software.

2. Windows PE boot disk.

3. The installer of the program itself, which can be downloaded from the official website of the program, or from other Internet resources.

We use the Windows PE boot disk to launch the working environment, since the developer did not include support boot disk with this product. GFI Backup can also work under the OS installed on the computer, but the functionality will be reduced to managing client machines.

As an example of such a program for backing up data, we will use GFI Backup Home Edition. The program is free and intended exclusively for non-commercial use, as indicated by the Home Edition prefix. It follows from this that the functions declared by the developer are not presented in full. You can download it from the manufacturer’s website http://gfi.ru/. The installation package size is only 10 megabytes. The installation process is extremely simple - run the installer, agree to the license agreement, select a location to install the program (in 99% of cases, the default location will be the best option) and that’s it.

The main program window is not overloaded with unnecessary functions. All the main features of the program are available immediately upon download, and in the form of “wizards”.

Fig.1 (Main program window)

To create an image, select “Backup”, with the help of which a backup copy of the data is created. When you click it, a wizard is launched that allows you to select copy objects and save location. The combination of source and destination locations is called a “task”.

On the General tab, the name of the task is indicated, as well as the name of the archive copy.

Fig.2 (Backup Settings Wizard).

In the Source tab, you need to select the location of the data that will be archived, for example, a copy of the entire C:\ drive.

The program can also archive registry keys, email client data and user settings. Archiving emails is a particularly useful feature. Supported email clients: Outlook, Windows Mail and Thunderbird.

Fig 3. (Selecting email clients).

It is possible to save custom settings various programs- from browser bookmarks to Total Commander settings.

Fig 4. (Window for selecting user program settings)

After selecting the data to be archived, in the lower left corner of the window you can immediately see the number and volume of elements that will be copied.

On the Destination tab, you select a location to store the archive that will be obtained as a result of archiving. It can be placed on:

Local disk (logically, this should not be the same disk from which the data copy is made).

Remote Windows network folder.

Removable media such as a flash drive or memory card

CD/DVD/Blu-Ray disc(s).

FTP server.

Select saving to local disk.

The Options tab contains important options. The first one is whether to compress the data or not. A compressed archive will take up less space, but it will also take more time to create. It is also possible to protect the archived copy with a password - either a Zip password (frivolous protection, in fact), or encryption using the AES algorithm (guessing a password for a person who is not supposed to see the contents of the archive will become a much more difficult task).

The program is made in such a way that full copying is carried out only with compression and encryption, differential copying with encryption, but without compression; and incremental copying without encryption and without compression. This was done to save system and user resources.

Figure 5. (Copy options)

Scheduler tab. Here you can select the frequency of copying. Among the options there is “run once”, “run manually”, at startup/shutdown Windows operation, by day of the week, once every N days and once every N hours. The frequency should be chosen based on the importance of the data and its volume (for example, copying 20 gigabytes of data every hour will only accelerate disk failure from overload).

Events tab. Here you can specify ways to indicate what is happening. For example, the program can send an e-mail to a specified address when errors occur or the archiving process is completed.

After viewing all the tabs and setting the desired options, the created task can be viewed by clicking on the “My Tasks” button in the main program window. If the task was configured to be started manually, you can start it in the same window by clicking the “Start” button. The archiving process will be displayed at the bottom of the window, as well as in the line with a description of the task.

Fig 6. (Task window)

To evaluate the performance of the program, 3 backup copies were made:

Full (MyBackup1 with compression) .

Differentiated (MyBackup2, with and without compression).

Incremental (MyBackup3 with and without compression).

Fig 7. (Browse files local disk P).

Time and speed of creating backups:

1. Full copying with compression - 34 min.; copy speed - 4.01 Mb/s.

2. Differentiated copy without compression - 14 min.; copying speed - 12 Mb/s.

3. Differentiated copy with compression - 18 min.; copy speed - 8 Mb/s.

4. Incremental copy without compression - 8 min.; copy speed - 4.9 Mb/s.

5. Incremental copy with compression - 12 min.; copying speed - 6 Mb/s.

The restoration process is very simple, just select “Restore” in the main program window and indicate which of the archives needs to be restored. When restoring files, the partition is formatted automatically and the size of the resulting volume will be the same as during copying.

As a result of experiments, this product did not perform well. After four attempts to restore each of the archives, we get the following picture:

The archive of a full copy was restored without errors in 4 cases.

A differentiated copy without compression out of four cases was fully functional in only two cases, but in other cases some files were damaged.

The differentiated copy with compression was successfully restored in only one out of four cases.

Both incremental copies were unable to restore the OS bootloader.

Based on this and taking into account the limited functionality of the free version of the program, we can conclude that this program Suitable only for backing up files and folders with user data, but not for copying the entire volume.

4.2 Review of Paragon Drive backup Workstation

4.2.1 General characteristics

The purpose of the Paragon Drive Backup program is to backup and restore operating systems and user data through the image mechanism. Along with this, Paragon Drive Backup has a number of other functions: copying and restoring individual files, basic capabilities for managing and editing partitions, functions for restoring the operating system bootloader, the ability to migrate from one computer to another (p2p) and to a virtual environment (p2v).

The Paragon Drive Backup family includes two products: Drive Backup Workstation and Drive Backup Server. The Drive Backup Server option differs in that it supports work with server operating systems, and also includes migration functions to a virtual environment (p2v). Otherwise, the functions of the programs are the same.

Paragon Drive Backup works on all Windows operating systems from XP to Windows 8 and Server 2008 R2.

The following file systems are supported:

NTFS (v1.2, v3.0, v3.1)

Paragon Drive Backup can also work without installation in OS. It is enough to unpack the program image onto a flash card or other media and boot from it. There are two types of Paragon Drive Backup images:

1. Standard based on Linux (created through the disk creation wizard).

2. Extended based on Windows PE (downloaded from the manufacturer’s website).

Supported media:

Support for MBR and GPT hard drives (including those with a capacity of 2.2 TB or more).

Hard drives with IDE, SCSI and SATA interfaces.

Solid State Drives (SSD).

AFD (Advanced Format Drive) drives.

Disks with a sector size other than 512 bytes.

CD-R, CD-RW, DVD-R, DVD+R, DVD-RW, DVD+RW, double-layer DVD-R, DVD+R, and Blu-ray discs.

Hard drives FireWire (IEEE1394), USB 1.0, USB 2.0, USB 3.0.

PC card storage devices (MBR and GPT flash memory, etc.) . System requirements:

OS:

Windows 2000 (32 bit version)

Windows XP (32 and 64 bit version)

Windows Vista (32 and 64 bit version)

Windows 7/8 (32 and 64 bit version)

Intel Pentium processor or equivalent with a frequency of at least 300 MHz

Hard drive with 250 MB of available disk space

4.2.2 Practical use

Installed in the operating system, Paragon Drive Backup allows you to create an image without stopping the operating system. This is achieved using Paragon Hot Backup technology, as well as Windows shadow backup technology - Microsoft Volume Shadow Copy Service. The latest technology is available starting with Windows Vista.

Figure 8. (Program start window)

The program allows you to create both full and differentiated or incremental backups. If you create a differential copy, only changes since the last backup are recorded in the archive. In the case of incremental - changes since the last full archiving. The archive can be sector-by-sector (the entire disk structure is copied, regardless of the file system), or file-based.

Differential copying is applicable only to sector-by-sector archives, and incremental copying, which is called “file addition” in the program, is applicable only to file archives. There are also complex archives that combine sector-by-sector and file backup.

Let's create a full backup of drive C, including the MBR. As a result, a complex archive will be created, within which the MBR will be recorded as a sector-by-sector archive, and everything else as a file archive.

Fig 9. (Image files)

Figure 9 shows that the folder contains files of two extensions: *.PBF and *.PFM.

The main ones are files with the extension *.PBF (paragon backup file). Inside these files are the contents of files and sections. Files with the *.PFM extension are additional archive description files that are used by the Image Explorer utility to quickly display information about the archive. When restoring data, files with the *.PFM extension are not required.

Archive.pbf is the main file that performs the combination of img_0... and img_1... .

img_0 - contains an archive of files, and img_1 a copy of the MBR.

When restoring, we specify each of these files in the dialog box, which is not always convenient.

You can also perform backups on a schedule - this is called a cyclic backup. The result of such copying is two images: The first image is complete, and the second is differentiated. This type of archiving is available only for entire disks.

Fig 10.(Setting up scheduled copying)

As a result of creating a disk image and restoring from it, it is clearly visible that the program does not perform both operations immediately. First, the program, by analyzing the file attributes, creates a list of changes and only then, after the parameters necessary for the operation have been set, clicking the “Apply” button starts copying. However, this mode can be disabled in the settings and the image creation process will take less time.

Figure 11. (Window to start backup).

Archive creation can be performed not only from under installed Windows. You can also create a boot disk, bootable Flash media, or create a so-called archive capsule.

A backup capsule is a special boot partition on your hard drive that contains a standalone running version of Paragon Drive Backup and storage space for backup copies. A capsule can be created as a primary partition or a logical partition within an extended hard disk partition and can be located anywhere on the hard disk: at the end, at the beginning, or between other partitions. Next, we try to create a backup capsule.

Fig 12.(Archive capsule settings window)

If there is no free space on a hard disk partition, then an archive capsule is created using the free space of other hard disk partitions. We create a capsule with the image on the free space of the hard drive D:\. After creating the capsule, you need to restart the computer and press the F1 key, while selecting the OS to boot, to boot into the capsule. The process of restoring an image from a capsule is the same as in the Windows program. This method widely used by manufacturers of laptops and personal computers.

Now let's try to create boot image programs (rescue disk). Bootable media can be created on a CD or on a Flash drive. When creating a disk, you can immediately add the necessary files to it.

Figure 13. (Rescue disk creation wizard).

Now you need to restart your computer and select the option to boot from external media. When booting from a disk, all necessary operations for backing up and restoring images are available, and the function of managing and editing hard disk partitions becomes possible.

Figure 14. (Emergency boot disk menu).

Figure 15. (Main program window.)

All operations are accessible and easy to perform. However, the process of creating an image takes much less time than creating it from an installed OS.

Archiving in the boot disk is carried out on local media; the image can also be saved to a network folder. However, working with network resources is implemented in an extremely inconvenient manner. It is necessary to manually set paths to network resources in order to mount them to local folder. There is a “Browse Network” button, but it doesn’t work.

Figure 16. (Connecting network storages)

The function of direct editing of sectors on the hard drive is also available.

Fig 17. (Sector editor for hard disk partition)

The Paragon Drive Backup boot disk allows you to restore Windows boot without restoring from a backup image, that is, there are functions automatic search installed copies of Windows, manual editing of boot.ini, etc. However, out of three attempts to restore the damaged boot.ini file, not one was successful.

Figure 18. (Windows Boot Recovery Wizard)

The developer included in the image the function of deploying the system on new equipment (p2p). In other words, the system image with all installed software can be unpacked onto other personal computers, which is important in the work of system administrators. Preparation for booting the system on new hardware is done on a deployed image. Those. First you need to deploy the image on a new PC, and then carry out the p2p procedure. By and large, the p2p procedure comes down to installing the necessary drivers for new equipment. First we need to select which copy of the OS on the hard drive we will restore, and then specify the drivers. Drivers can be downloaded automatically (from a specified folder) specifically for the hardware used on the new PC.

Fig 19.(Menu for selecting actions when loading drivers)

Based on the experiments performed, we can conclude that this product performs the stated functions quite well, except for the network copy function and the system boot recovery function without affecting the image. For each backup type, four copy and restore attempts were made. All attempts were successful.

Product advantages:

P2P technology is included in the price and comes with the product.

Ready-to-use boot disk based on Windows PE.

Flexible pricing and licensing policy.

Product Disadvantages:

Storing the archive in several files.

OS restoration tools do not work without the need to restore from an image.

Working with network resources is implemented extremely poorly.

Complex software interface.

4.3 Acronis True Image Home overview

4.3.1 General characteristics

Acronis True Image Home is designed to create a backup image of the system, local disk, and files. It can automatically, at a given time, archive the necessary data (system, disk, folder, file). Archiving can be done in different ways:

Create a new image every time;

Update an existing one by creating a small image that includes only the changes that have occurred to the data since the creation of the previous image.

In addition to creating images, Acronis can restore data that was archived in an image. When creating a backup image of the system, all files from the specified disk are saved to the archive, that is, all programs, all registry paths, all system settings made before archiving the disk. One of the common ways to use the program in practice is to restore the system from a previously created image, booting from DOS from a special Acronis boot disk. In this case, in approximately 25 - 40 minutes, the system is restored with all the settings, drivers and software that were in the system at the time the archive was created.

Supported Operating Systems:

Windows® Vista/7 32 & 64 bit

Windows® XP SP 2, SP 3

Windows® XP Professional x64 Edition SP2

Acronis True Image Home allows you to create bootable CDs for complete recovery of information on hard drives/partitions created by Windows XP/Vista/7.

Minimum system requirements:

Pentium processor or higher;

RAM 256 MB;

Optical drive with the ability to write CD-R/RW or DVD +R/RW for creating bootable discs.

Supported Hardware:

Internal and external hard drives;

Network drives and storage devices;

CD-R(W), DVD+R, DVD+RW, DVD-RAM, BD-R (Blu-ray);

ZIP® Jazz® and other removable storage media;

P-ATA (IDE), S-ATA, SCSI drives, removable media with IEEE1394 (Firewire) and USB 1.0 / 2.0 interface, flash memory cards;

Supported file systems:

FAT16/32, NTFS, Linux Ext2, Ext3, ReiserFS, Linux SWAP;

Sector-by-sector copying for unknown or damaged file systems

4.3.2 Practical use

After installing the program and restarting the system, Acronis TrueImage is ready to use.

The right window contains icons, double-clicking on which launches basic operations. When you single-click an icon on the right side of the main program window, a hint appears on the left side, informing you about the purpose of the selected icon. From the main program window you can perform the following actions:

1. Create image - launches the image creation wizard, which makes an exact copy of the entire hard drive or a separate partition and saves it to a file on the hard drive, in the security zone, on a network drive or on removable media.

2. Restore image - launches the image recovery wizard. The wizard requests options for restoring a partition or the entire hard drive from an image file that was created earlier and starts the recovery process.

3. Mount image - launches the Mount Image Wizard, which assigns a letter to the image file of a hard disk or partition and uses the image as a regular disk.

Similar documents

Types of media used to select backup and data storage technology. Recovering data on a clean computer. Types of backup programs. Overview and purpose of the Paragon Drive backup Workstation program.

course work, added 01/26/2013


Types of backup: incremental, differential and full. Technologies for storing backups and data. Review of backup programs. Features of Deja Dup. Linux operating system console commands. Setting an encryption password.

course work, added 04/30/2014


Full, differential and incremental backups. Technologies for storing backups and data. Restoring data from backups on a clean computer. Application and comparison of backup software products.

thesis, added 09/08/2014


Basic methods for backing up and restoring OS Windows 8. File history, creating a restore point. Selecting backup tools. Possibilities of backup programs. Features of modeling and implementation of the task.

course work, added 12/24/2014


The concept of backup as a strategic component of data protection. Protect your backup database or directory. Defining the backup time window. Create and maintain public reports and open issue reports.

abstract, added 04/05/2010


Basics of backing up file resources. Types of file backups. Instant recovery points. Planning for data archiving. System state backup. Network administrator tasks. Reverse changes and shadow copies.

presentation, added 12/05/2013


The main virtual machines VMware and Virtual Box, their characteristics, advantages and disadvantages. Comparative analysis of backup tools. Platform installation and configuration. Server setup and installation. Setting up Windows XP.

course work, added 02/04/2013


Network structure of Prime Logistics LLC and organization of its protection. Development of a network segment for network backup. Selecting hardware for network backup. The process of implementing a system to prevent data loss in the network.

thesis, added 10/20/2011


test, added 01/06/2014


Purpose, structure and applicability for organizing a centralized backup system. Formation of a list of functional tasks that need to be solved during the implementation of the implementation project. Highlighting risks and proposals for minimizing them.

Protecting data (which includes installed software) from deletion or corruption is not an easy task even in the absence of deliberate actions on the part of attackers. As a rule, to solve it it is necessary to use a set of software and technical measures, the main of which are:

data backup;

thoughtful configuration and maintenance of the required (“safe”) values ​​of system parameters;

advance installation and mastery of specialized data recovery software.

The listed measures must be provided for at the stage of developing the organization's security policy and reflected in the relevant regulatory documents (in the security policy document, in private instructions of structural units and in the job responsibilities of performers).

Data backup

Backup can be considered a panacea in almost all situations involving data loss or corruption. However, backup will only prove to be a truly universal “cure” if you follow the rules for its use. Features of restoring various types of data based on backup copies will be given in the relevant chapters of the section now Let's look at the general principles of backup.

Archiving and Backup

These two concepts are so often used together in publications and when working with data that they sometimes even begin to be perceived as synonyms. In fact, although archiving (the English term archiving) and backup are great “friends,” they are not twins or “relatives” at all.

What is the meaning behind each of these terms?

Archiving very close to the creation of non-computer, “paper” archives. An archive is a place adapted for storing documents that have either lost their relevance or are used relatively rarely.

Documents in the archive are usually ordered (by dates, logic, authorship, etc.). This allows you to quickly find the document you are interested in, correctly add a new document or delete an unnecessary one.

Almost all of the above features are also inherent in electronic archives. Moreover, the leading role in their creation is played by the ability of archiving programs to compress the archived data, thereby saving space for their storage. It was this ability of archivers that made them friends with backup programs, but more on this a little later.

Target Reserve copy on a computer - to increase the reliability of storing those data, the loss of which may upset (to put it mildly) their owner. For particularly valuable data, two or more backup copies can be created. As a rule, when backing up you have to solve two interrelated problems : what data to copy, and how often. On the one hand, the more often you copy, the less effort you will have to spend on restoring a document lost, for example, due to a hard drive failure. On the other hand, creating each new copy requires time and storage space. In many cases, it is the use of compression methods implemented in archiving programs that allows you to select the appropriate parameters for the backup procedure. Essential difference between backup and archiving is that at least one backup copy must be created not on the hard drive storing the original, but on an alternative medium (CD, etc.).

Another difference between archiving and backup given below.

You can create an archive, including rarely used data, and save it either directly on your computer’s hard drive or (preferably, but not necessarily) on another medium. And after that good luckupload source files (originals).

Procedure backup requires the obligatory preservation of the original(that is, the data with which the user works). Backup is intended primarily to improve safety of data that continues to be used in operation (that is, they change periodically). That's why backups should also be done periodicallyski update. In this case, the use of additional storage media (storage devices) is mandatory. Ideally, each copy should be stored on a separate medium.