Creating a data archive on an external hard disk by copying and recovering data. Restore data on backups. Problems when creating the data archive by copying

Methods and Toolsdata data

Data protection (to which the installed software can be attributed) from the removal or distortion of the problem is not easy even in the absence of intentional actions on the side of the attackers. As a rule, it is necessary to use the Software Software Software complex, the main of which are:

data backup;

thoughtful configuration and maintenance of the required ("safe") values \u200b\u200bof system parameters;

adjustment and development of specialized data recovery software.

These measures should be provided for at the development policy development phase of the Organization and are reflected in the relevant regulatory documents (in the Security Policy Document, in the private instructions of structural divisions and in the official duties of the performers).

Data backup

Backup can be considered panacea in almost all situations associated with loss or distorting data. However, a truly universal "medicine" backup will be just if you follow the rules of its application. Features of the restoration of various types of data based on backup copies will be given in the respective chapters of the section now Consider the general principles of backup.

Archiving and backup

Two of these concepts are so often used jointly and publishing and when working with data, which sometimes even begin to be perceived as synonyms. In fact, although archiving (English term Archiving) and backup (backup) are big "friends", they are not twins at all and do not "relatives" at all.

what is behind each of these terms?

Archivingvery close to the creation of non-computers, "paper" archives. The archive is a place adapted to store documents that either have lost their relevance or are relatively rare.

The documents in the archive are usually ordered (but the dates, by logic, on authorship, etc.). This allows you to quickly find the document of interest, correctly add a new document or remove unnecessary.

Almost all listed features are also inherent in electronic archives. Moreover, the leading role in their creation is played by the skill-archive program to compress the archived data, thereby saving the place to store them. It is this ability of archivers and "made friends" with their backup programs, but more about it a little later.

purpose reserve copyon the computer - to increase the reliability of storage of those data, the loss of which can disappear (to put it mildly) their owner. For highly valuable data, two or more backup copies can be created. As a rule, during backups you have to solve two interrelated problems. : what data is copy, and how often. On the one hand, the more often the copy is performed, the less you will have to spend the forces to restore the document lost, for example, due to the hard disk failure. On the other hand, the creation of each new copy requires the cost of time and place for its storage. In many cases, it is the use of compression methods implemented in archiving programs that allows you to choose the appropriate parameters of the backup procedure. Essential difference backup from archiving It is that at least one backup must necessarily be created not on a hard disk stored by the original, but on an alternative medium (CD, etc.).

Another difference between archiving and backup Led further.

You can create an archiveBy turning on it rarely used data, and save it either directly on the hard disk of the computer, or (which is preferable, but not necessarily) on another carrier. And after that breakpour source files (originals).

Procedure backup involves mandatory preservation of the original (that is, the data with which the user works). Backup is intended primarily to increase save data that continue to be used In work (that is, periodically change). therefore backup copies must also periodicallyski updated. In this case, the use of additional data carriers (storage devices) is mandatory. Ideally, a separate medium should be left for storing each copy.

Backup methods

Backup is usually carried out in accordance with one of the three main methods: complete, incremental and differential .

Using full reservationeach time you copy the entire dataset. For example, it is copied entirely file system, database or specified disk directory. This method takes a lot of time when recording and leads to a large consumption of backup media. On the other hand, in this case, the recovery of information is carried out faster than with any other method, since the backup corresponds to the current state of the entire dataset (taking into account the periodicity of copying). Full copy is the most attractive solution when backing up system information and serves as a starting point for other methods.

Incremental(or added) The method is based on a sequential partial backup update. On the first stage A full copy of the data set is created. Subsequent backup sessions are divided into two types: partial copying and complete. For next partial Only files that were modified compared to the previous partial copy are placed on the backup media (in fig. The incremental backup procedure for the weekly cycle) is shown schematically). Modified are considered files from which fromcontent, attributes or permissions are changed. After the time spent specified by the user (or the system administrator) again a full copy is created.And then the cycle is repeated. This method is the fastest strut of viewing of intermediate copies and leads to minimal consumption of backup media.

However, the recovery procedure takes a lot of time: the information first needs to be restored from the full copy, and then sequentially from all partial (incremental) copies. However, this is the most popular backup method.

Fig. Incremental backup scheme for weekly cycle

For differential(difference) method at the first stage also a full copy is created. At subsequent stages, only files changed from the full copy time (in fig. The differential backup scheme for the weekly cycle) is copied. Through a given time interval, a full cycle is renewed, that is, a full backup copy of the data set is again created. Compared to the incremental method, the differential copying requires more time to create a partial (differential) copy, but the restoration of information is performed faster, since only two copies are used: the full and last differential.

The main problem of incremental and differential copy is the problem of selecting a reliable file modification criterion. Usually, an Archive attribute is as such (for DOS / Windows systems), the file creation / modification time, the file size or the control sum of the file content. Unfortunately, they all have certain disadvantages associated with the features of attribute processing and access rights by individual application programs.

Note

Someof modern softwarebackup funds offer a fundamentally different approach to creating backup copies, which is sometimes called copying on the fly. His idea is that any changes to the files specified by the user when configuring the program are immediately transferred to the backup. With the obvious simplicity of the method, it has a number of shortcomings. The main one lies in the fact that the changes made may be due to the erroneous actions of the user or the operation of malicious programs. As a result, the return to the "correct" version of the file may be impossible.

N hard

Fig. Differential backup scheme for weekly cycle

Another problem is related to the choice of the periodicity of creating partial copies and with the number of such copies within the full cycle.

On the one hand, the more often copying, the more the more "fresh" information will be saved as a backup. On the other hand, each backup session requires certain additional costs: and time, and backup media.

To optimize the number of reserve media used, special carrier replacement algorithms have been developed (the so-called schemesrotation Nov. pitel). The most often use the following schemes:

disposable copy;

simple rotation;

"Grandfather, Father, Son";

"Khanaya Tower";

"10 sets."

Disposable copying- This is the most simple scheme that, in fact, does not provide for the rotation of the carriers. When using it, the redundant data is copied each time to the same rewritable medium (for example, on a CD-RW or diskette). Another embodiment of such a scheme is the next copy of the data is placed on a new non-rewritable medium (for example, on CD-R). Such a scheme is commonly used in cases where the amount of data redundant is small, or when the reservation is not regular (for example, when a single backup copy of the CD-R system is created).

Simple rotationit implies that a certain set of carriers is used cyclically. For example, the rotation cycle can be a week, and then one medium stands out for a specific working day of the week. With this scheme, a complete copy is usually done on Friday, and on other days - partial copies (incremental or differential). Thus, for the weekly cycle, it is enough to have five media. After the cycle is completed, everything is repeated first, and the record is made on the same media. The disadvantage of this scheme is that it is not very well suited for the logging of full copies, since the number of carriers in the archive is growing rapidly. In addition, quite frequent rewriting of partial copies on the same carriers leads to the wear of the latter and, accordingly, increases the likelihood of their failure.

Scheme"grandfather, father, Son "it has a hierarchical structure and involves the use of a set of three carrier sets. Once a week, a complete copy of the computer disks is made, incremental (or differential) copy is carried out daily. Additionally, once a month is made another complete copy. A set for daily incremental copy is called "Son", for the weekly - "Father", and for the monthly - "grandfather". The composition of carriers in daily and weekly sets is constant. At the same time, in the daily set, each carrier corresponds to a certain day of the week, and in the weekly set - each week of the month. The media from the "monthly" set is usually not updated and postponed to the archive. The disadvantage of this scheme is that the archive contains only the data that occurred at the end of the month. As with simple rotation, daily copies are subjected to significant wear, while the load on weekly copies is relatively small.

Scheme "Hanoic Tower"rarely used by users of "home" computers. It is built on the use of several sets of carriers. Their amount is not regulated, but is usually limited to five or six. Each set is designed for a weekly copy cycle, as in a simple rotation scheme. Each set contains one media with a complete weekly copy and carriers with daily incremental (differential) copies. The table shows the rotation scheme for five carrier sets.

Rotation scheme "Hanoic Tower" for 5 setspossels

Each next set is used twice as much as the previous one. Thus, the set N1 is overwritten every two weeks, set N2 - every four weeks, etc.

Diagram "10 sets"also used infrequently. As follows from the name, the scheme is designed to use 10 sets of carriers. A period of 40 weeks is divided by ten cycles. Within a cycle behind each set, one day of the week was fixed. After a four weekly cycle, a transition to the next set is carried out. For example, if in the first cycle Monday corresponded set 1, and for Tuesday - set 2, then in the second cycle, Monday will correspond to a set of 2, and Tuesday - set 3. Such a scheme allows you to evenly distribute the load and, as a result, align the wear of the carriers.

Backup software and hardware

The current backup programs are eliminated by users and system administrators from the need to "manually" track the frequency of creation andreserve updates, replacement of carriers, etc. Pravda, the list of service provisions provided by such software programs significantly depends on the program category. All backup programs can be divided into three categories:

Initial-level systems included in operating systems. These can also include most free and conditional backup programs. These programs are intended for individual users and small organizations.

Mid-level systems; With a relatively low price, they have extensive backup and data archiving capabilities. Such systems are quite a lot (in particular, ArcServeit Computer Associates, Backup Exec from Seagate Software and Net Worker Company Legato Systems).

The top-level system is designed for backup and archiving in complex heterogeneous environments. They support a variety of hardware platforms, operating systems, databases and corporate level applications, have integration tools with network management systems and provide backup / archiving uses using a variety of storage types. Such systems include ADSM of the GUM and OpenView OmniBack II from Hewlett Packard. However, for many organizations (not to mention individual users) they are quite expensive.

One of the important characteristics of backup programs is a list of supported types of interchangeable media.

At the same time, when creating a backup in "manual" mode, you are free to use any of the data storage devices currently. Their list with a brief description is given in Table.

Data storage devices used during backup

Device type	Dignity	disadvantages
Hard Disk (HDD)	B. Capacity, speed (), high reliability, durability, multiple overwriting, low cost, the ability to download a backup copy	Insecurity during transportation, exposure to emissions, (connection ..)
	Acceptable speed and speed, n. Cost, reliability, durability	Capacity, not all types of PCs are equipped with
	Large container, also that CD ...	Specialization, not all types of PCs are equipped with
SD, MS memory cards, (CF), MMC, ...	Capacity, speed, reliability, acceptable speed and speed, the possibility of use for transferring Mr. Multi-type
Flash memory modules
External hard drive
Mobile Rack, Streamer, floppy,Zip., Ziv, magneto-optical

Brief results of a comparative estimate of the parameters presented in the carrier table.

This or that rotation scheme can be implemented only for devices with interchangeable carriers, which include optical (CD and DVD) (and magneto-optical discs). At the same time, for the "average" user, one carrier with a capacity of several gigabytes is clearly "vicious" to store one copy of the data. The only exception is when it comes to creating an image of a whole partition of a hard disk.

Thus, on the set of characteristics, the optimal option today can be considered a backup on the basis of rewritable optical disks (CD or DVD).

Regarding the use of a hard disk as a backup media, you need to make several additional comments.

First: if there is a need to store a hard disk with a backup of data separately from the computer on which they were created, then it is advisable to use (the so-called portable Disk(Mobile Rack) Hard disk with USB interface. .

Second: If your computer runs running the Windows XP Professional operating system, and at least two hard drives are installed on it, you can use fault tolerant RAID-1 and RAID-5 technologies.

Third: if there is a single hard, the disk is quite large tank, it is advisable to split it into several logical partitions, one of which (at least) can be used as a backup disk; Such a logical backup disk will be protected from many nastacks threatening "workers" sections (although, of course, not from all);

Technology RAID

In sufficient major organizations for backup criticallyimportant data applied technologyRAID (Redundant. Array. of. Independed. Disks. - excess array of independent drives) based on the systemsocially configured hard drives.The initial purpose of creating technologyRAID There was a raising producedisk memory due to the use of several interrelatedhard drives instead of one.

Total today with industrial standards providedbut eight levels (modifications)RAID:

RAID-0- Association of space of several physical disksin one virtual volume for which the alternation method is applied(striping., OT.strip. - "Strip"): The information is divided into blocks, alternatebut written on all volume drives (Fig. 4.3).RAID-0 Ensurehigh data exchange speeds, but reliable virtuallythom volume is somewhat lower than that of any other level and below the reliability of each of the incoming in that discs, since when it fails, thoughone of them all information is lost.

RAID-1 - duplication, or "mirroring" (mirroring.- Mirrorreflection) disks. In this case, information simultaneously recordedtwo (usually) disk. At the failure of one of themthe data is read from the "Mirror". To this level also refer toduplex volumes (Duplex VOLUME.) when physical disks used as mirrors must necessarily be connectedto different controllers. Implementation of recovery after failures UsageRAID-1 is quite simple, but there is a high(100%) redundancy.

RAID-2 - implies the creation based on several physical disone array (volume), the data in which is recordedusing the control code (chemming code). For storagethe control codes are given a specially highlighted disk.RAID-3 - array with alternation and the use of parity code forerror detection. Parity information, as in the case ofRAID-2, stored on a separate disk, but has less redundancy.RAID-4 - like level 3, but the data are divided into blocks, recordsyou can have different disks, and there is a parallel appeal to several blocks, which significantly improves productivity.RAID-5 - similar to the level 4, but the parity information is not storedon a dedicated disk, and cyclically distributed between all diskami Tom.

RAID-6 - in contrast to level 5, uses two independent schemesparity that increases both redundancy and storage reliabilityinformation.

RAID-7 - a fault-tolerant array optimized to increase productivity. This levelRAID ONLY SPEE is supportedcalisated OS.

Disc 2.

TomRAID

Fig. Usage schemeRAID-0

TechnologyRAID To date, it is implemented as at the hardware level,so and programmatically.

The hardware implementation is more efficient and the basison on connecting hard drives through specialRAID-Controllers. Such a controller serves as a communication with the server (workstation), generating redundant information when recording and checking when reading, racesinformation over disk information in accordance with the Functional Algorithmrings.

Principle of operation of software managed volume RAID-1 consist of

next.

Based on two sections located on two different physical disks,created so-calledmirror(Mirror. VOLUME.). He is assignedthe own letter of the disc (source disks are deprived of suchso), and when performing any operations on the data of this volume, all ofchanges are synchronously reflected in both source sections. When leavingbuilding (refusing or fails) of one of two disks The system automatically switches to work with the remaining "last hero". With the emergencethe user can split the mirrors, and thendinent a good section with another section in a new mirror volume. In a mirror volume, you can enable almost any partition, includingsystem and bootable.

Restore data on backups

You can also repeat that the use of data backup is the easiest and most reliable way to ensure their safety. However, many users prefer to save a few minutes on creating a backup, to then spend a few hours (or even days) and a lot of nerve cells to restore lost information. Especially strangely to put up with this today, when there is a mass of tools that require from the user just to specify "when, and how much" reserved.

When choosing a specific backup tool, it is advisable to take into account the following factors:

list of implemented backup methods;

supported data carriers;

ease of use (user interface quality).

Technology of work of almost all Non-type backup programs: The user creates the so-called task in which the composition of the copied data is specified, the backup method (full, additional or difference), the frequency of creating a copy, its location and (possibly) some other parameters. To restore the data (specific file or a whole disk), you must specify which copy you should use, and set the update mode (with the original replacement or without any). This technology is applicable both when recovering "user" data and system information. However, the restoration of system information has certain features that will be discussed in the chapter "Data Recovery".

The following are briefly considered two standard (and therefore the most accessible) backup and recovery tool included in Windows XP Professional: programData archiving andprogramSystem Restore. The first of them is more "universal", and can be used for any data sets, the second has a more specific destination - restore system parameters.

Data Archiving Program (WindowsXp.Professional)

Program version Data archivingincluded in Windows XP Professional, supports various types of media, which allows you to back up to any storage device supported by the operating system. Such devices include any flexible or hard drives, magneto-optical drives and other devices (and not just streamers, as in the version of this program for Windows 98).

Note

To use the backup program, you must start the removable memory service. Like any other serviceWindows Xp. Professional It can be launched from the administration console.systems.

Windows XP to create a backup copy of data are used so-called snapshots of TomaVOLUME SNAPSHOTS. The essence of the technology is as follows. At the time of initiation of the backup procedure, a snapshot of volume is created. After that, the data is redundant, but not from the source volume, but from its picture. This allows you to save the ability to access files during the backup process.

Program Data archiving(Fig. 4.4) has the following main possibilities.

You can quickly create a backup copy of the optical volume. You can copy the optical volume command (Dupopt). This command copies the sectoral volume and creates an exact copy of the source volume that differs only by the volume identifier and the date and the creation time.

In the release of V7R2 with the applied PTF Si57188 \u200b\u200band in subsequent releases, carriers with support for IPL can be copied to media with various physical characteristics.

Fill in the following fields:

From Toma
Therein
Identifier Toma
Clear

Media without support for IPL

When creating a copy, the target carrier must be at least no less in volume than the original one.

If the source media is formatted with * UDF, the Dupopt command tries to release more space on the target carrier if the latter is greater than the source. After creating a copy on the target carrier, the volume determined by at least the following values \u200b\u200bremains:

Available for use the volume of the target carrier.
Double-volume base carrier.
The double volume of the initial carrier, where the initial carrier was first formatted.

For example, when copying a carrier of 1 GB with a 2 GB carrier, the volume of the target carrier is available for use after copying is 2 GB. When copying a carrier with a volume of 1 GB per carrier of 2 GB, followed by copying the latter on a 4 GB carrier available for use, the volume of the last target carrier after copying is 2 GB.

Note: The source and target carriers should have the same block size.

IPL support media

In the release of V7R2 with the applied PTF Si57188 \u200b\u200band in subsequent releases in the parameter in the (TOVOL) Dupopt commands, you can specify a new special value * boot.

The size of the target carrier must be sufficient to place the boot area and all files from the source media.

Specifying * BOOT Values \u200b\u200bin the parameter in the Dupopt command means that the bootable area and all files from the source media should be copied to the mounted target carrier. Copying is performed even if the physical characteristics of the target and source optical volumes do not coincide. This BOOT value allows you to copy an existing DVD with support for IPL or distributed media to a removable disk (RDX) or flash media.

The following example of the Dupopt command shows how to copy the IPL support media, mounted on the DVD device named OPT01, on the RDX media, already initialized and mounted on the RMS01 device.

Dupopt FROMVOL (* Mounted) Tovol (* Boot) Clear (* YES) fromdev (OPT01) TODEV (RMS01)

The command of this example copies the optical volume mounted on the OPT01 device, on an optical volume mounted on the RMS01 device. The optical volume on the RMS01 device is initialized before copying. At the end of the copy, the TOM will support the IPL on the RMS01 device.

Note: Special value * boot is permissible only if the source volume contains carriers with support for IPL.

Instruction

One of the most common copy protection systems is StarForce. The creators of the system guaranteed the manufacturers of games absolute copy protection, however, with a competent approach, the disk can still be copied. Consider copying a protected disk using the Alcohol program 120%. This program can be easily found in and install on your own. Alcohol 120% not only copies the data from the disk, but also transfers information about its physical structure into a special file, in the process of writing the emulator readable, which in turn will emulate delays imitating StarForce protection.

Insert the copper disk into your drive. Launch a 120% image creation wizard in the Alcohol program. Do not forget the "Emulator" function, the data type to select StarForce 1.x / 2.x. Click "Next". The program for successful copying will need to first create a virtual image. Give the name to the file being created, select * .mds and specify the program folder to which it will write the disk image. Disconnect all unnecessary active applications, set the read speed to a minimum. The more carefully Alcohol 120% read the source disk, the greater the chances that he will be able to cope with protection. Depending on the power of the computer, after a while, creating a virtual image will be completed, you can remove the disk from the drive.

With the recorded virtual way you can do differently. The best solution will be the timing of the image to the virtual disk. Alcohol 120% on this, strictly speaking, and specializes. But you can try and burn it to the disk physical. When recording Alcohol, 120% believes from the information information on protection and will try to fully recreate the physical copy of the disc needed to you. The recording speed, as and when reading, you need to choose the minimum. After some time, your disk will be ready.

Sometimes there is a need to create disc With copy protection. For example, every second operator who is engaged in video filming of events (holidays, matinees, weddings) creates secure discs. But what if you recorded such a disc, and the original was lost on your computer? Most disc With the protection from recording, it is arranged in such a way that information from these disc Reads, but not copied. Some programs that create images can cope with this problem. disc with support for protection systems.

You will need

Alcohol 120%

Instruction

One such program is the Alcohol utility 120%. This program will create a full-fledged image on your hard disk. Alcohol supports most disk formats, allows you to work with 30 images at the same time. Also, this utility allows you to copy the discs that you have been recorded using protection.

Run the "Image Making Wizard". Select your writing drive - select the data type - StarForce 1.x / 2.x. Also pay attention to the "Data Positioning Measurement" item (Data Position Measurment). Tick \u200b\u200bthe checkbox this item. Click "Next".

Enter the name of the future image. Click on "Start" - select the speed of your disk. Speed \u200b\u200bput the minimum. It will take a lot of time, but the quality of the image will increase at times. It is worth closing all open programs, because They can occupy system resources, which can affect the future disk image. Next, click "OK", expect the completion of this operation.

Sources:

How to remove the protection of the disk recording, and then the defense interferes with the record

Each person has its own secrets. And the more computers penetrate people, the more secrets they trust storing the car. But the preservation of private information on a personal computer is not at all safe. Even if user accounts are password-protected, even if the password is installed on the BIOS, anyone who has physical access to the computer, can turn off the hard disk and copy information from it. And when people are aware of this frightening fact, they involuntarily think about how to encode disk And thereby reliably protect your data. Fortunately, currently there are reliable free programs that provide the necessary functionality.

You will need

Free TrueCrypt data encryption program available for download on TrueCrypt.org.

Instruction

Start the process of creating a new encrypted volume. Run TrueCrypt. Select "VOLUMES" and "CREATE NEW VOLUME ..." in the menu. A wizard of creating a new volume "TrueCrypt Volume Creation Wizard" will open. On the Wizard page, select "Encrypt a non-System Partition / Drive" and click "Next". On the next page, select "Standard TrueCrypt Volume", click the "Next" button. On the third page, click the "Select Device" button. In the Select A Partition or Device dialog that appears, select diskwhich must be encrypted, click "OK". Click the "Next" button. The next wizard will open. Select "CREATE ENCRYPTED VOLUME AND FORMAT IT", click "NEXT". Next, specify the encryption and hashing algorithms in the current page drop-down lists, click the "Next" button. Click the Next button again. In the "Password" field, enter the password for disku, in the "Confirm" field, confirm the entered password. Click "Next".

Format disk. Move the mouse cursor for some time within the current page of the encrypted volume creation wizard. This is necessary to generate random for encryption algorithms. In the drop-down lists, select the file system and the size of the volume cluster. Click the "Format" button. In the warning dialog that appears, click the Yes button.

Wait for the formatting process. It may take a long time if the formatted section diskand a large enough. In the dialogs that appeared after formatting, press the "OK" buttons. Press the "EXIT" button.

Mount the new encrypted volume. In the main program window, click "Select Device ...". In the dialog that appears, select the encrypted volume, click "OK". In the list in the rather part of the application window, select any letter diskbut. Press the "MOUNT" button at the bottom of the TrueCrypt window. There will be a dialog for entering a password access to disky Enter password. In the list disknEs will appear new diskmarked selected earlier.

Video on the topic

note

After formatting the disk, the TrueCrypt program all information on it will be deleted. In addition, the disk will become more readable. Before encrypting the disk, make sure that all important information has been saved.

Helpful advice

Use TrueCRYPT container files to store encrypted information. This is a more flexible approach than encrypting entire sections. File container can be moved to another computer and mount it there as a separate disk.

Sources:

How to put a password on a hard disk without special programs

Sometimes there are situations where the operating system does not allow you to delete or move files on your own hard disk. Most often it occurs because you like the user does not have enough rights to delete certain files. You need to change your access rights and the corresponding permissions.

You will need

- a computer;
- Administrator rights.

Instruction

Find files in "My Computer", operations on which you cannot perform. For example, this is a Games folder. Click on the Right-click folder and select "Properties" in the drop-down menu. It can be a completely any folder that is located on the local computer disk or. It is also worth considering the fact that some system files and folders may not be displayed, as the system data browsing functions are disabled.

Click the Security tab and find your name in the list of users. Click on it with the left mouse button and check the list of permissions located just below. If the required flags are not, click the Edit button. Check the checkboxes all the permissions you need. Click "OK" and "Apply" so that the changes you are preserved. Close all the unnecessary windows to continue protection operations from local disks.

For normal operation of any business, operational access and reliable storage of information are important. Technical problems, update errors, cyberatics and other forcemen, in turn, can lead to loss of data, and, it means financial losses, up to the full collapse of the company.

We have already written in the article about 3 strategies about the deplorable examples of large companies and the importance of backup.

Every day it becomes clearer, to provide backup information (backup) on the server - the need for number one for any business. And pleases what to restore the entire event archive, documents and programs - is realistic with the competent selection of backup methods.

In the event of an emergency failure, it is a backup copy of all data to ensure full operational access to all information stored on damaged media.

To copy information from digital media, different backup and storage methods are applied - it is backup (Backup) and data redundancy (Redundancy). They are different, but sometimes can be used at the same time.

Data redundancy allows you to restore files immediately after failure. The principle of operation is that when losing access to the file, it is replaced with its copy. It helps to avoid downtime in the site or application and allows the server administrator to return the system to the original operating state.

It would seem that the optimal decision, but he has a number of significant flaws. If the system failures occur, all data can be lost. In addition, each operation in the system affects the saved copy. So, in the case of malicious operations in the system, errors will remain in all subsequent data copies.

In the case of backup, the data is returned to their initial state, and they can be restored for conditionally any period of time depending on the depth of the redundancy.

Backup Critical Information Even in case of failure of a separate application, the entire machine or loss of individual data allows you to re-deploy, restore or access this information. Minus Backup, unlike a redundancy approach in the fact that it takes time and equipment to recover information. But the data is accurately saved and access to them is guaranteed, and with those parameters and from the moment when it is necessary for the user.

The ideal option for storing valuable information is automatic backup to a remote server that does not depend on external influence and is regularly moderated by administrators. We in SmileServer in each tariff offer backup and storage of these customer data on servers in Germany, which ensures their safety and safety in the case of any technological failures.

Backup strategy on server

The optimal strategy to ensure the safety of data and the uninterrupted operation of the user resources is to combine backup and data redundancy technologies. When dealing with one host, the machine will continue to work without failures, as the migration mechanism works, and thanks to the backup technology, all files will be restored from the hard disk.

To configure the backup, you can use a number of commands, such as CP and RSYNC, manually. But to automate the copying process, this approach requires the creation of individual scenarios, which is difficult and not always effectively. For business tasks, backup is carried out using special tools and utilities, such as BackupC, Bacula and Duplicity, which we suggest considering more details.

Automated bacapov solutions

Special comprehensive backup solutions make the procedure easier and do not require active participation and multi-level setup from administrators.

BackupPc.

The solution is applied both for Windows and for Linux, installed on a dedicated server or VPS, which acts as a backup server. Then this server downloads user files. All the necessary packages are installed on one server, and only access to the disk on the protocol or SSH is needed. On SMILE Server virtual servers, you can implement the backupp SSH keys when deploying without using additional software.

Bacula.

Universal and technically challenging program backup hosts according to the client-server model. In it, each backup task is set as a separate job (JOB). This approach allows you to perform a fine setting, connect multiple clients to one repository, change the copy schemes and extend functions using additional modules.

Duplicity.

This is a real alternative for all existing backup tools. The main difference between this software solution in the use of GPG-encryption while maintaining information, which improves storing data.

The main advantage when using GPG encryption for backup is that the data is not stored as a simple text. Only the owner of the encryption key can have access to them.

Block backup

This type of backup is also called "Creating Images". Technology allows you to copy and restore data for entire devices. If, with standard backup copies, copies of individual files at the file system level are generated, then when creating images, data is copied by blocks without separation to files.

The main advantage of block backup is high speed. The fact is that backup based on files initiates the process again for each individual file, and when blocking files, each block accounts for much more than one.

All listed technologies and numerous ways to configure self-backing data will help avoid a catastrophe in the form of irrevocable loss of valuable information or data of your customers.

When placing information on external media (this, thus, it is about the physical level of its storage) a unit of information is the physical record of the media, which hosts one or more logical records. The named holistic set of homogeneous information recorded on the outer carrier is called the file. In fact, the main data storage unit on the B3Y is filed, and it is with files that are produced by certain conversion operations (add data, their adjustment, etc.).

To place data on external media, the following types of data file structures are used.

consistent;

index-consistent;

library.

Data in file structures are possible two access options - consistent or arbitrary. With consistent access (processing mode), the file entry is transmitted from the publication in the RAM in the order in which they are placed on the carrier. On the contrary, in arbitrary access mode, they can be removed from the file as it requires a specific application program.

In serial files, recording are located on a carrier in order of their receipt. Through the buffer, they are all sequentially transferred to RAM for processing.

Backup

Arbitrary processing mode is impossible here, since to search for an entry for any sign, you need to conduct a consistent search for all records. Removed entries are physically excluded by creating a new file.

An example is simple text files (ASCII files). They consist of strings of characters, and each string ends with two special characters: "Return carriage" (CR) and "Row Transfer" (LF). When editing and viewing text files on the monitor screen, these special characters are usually not visible.

In direct files, there is a direct connection between the recording key and its location on the carrier. When you enter a logical entry into files, the conversion or display of the recording key to the memory address by which it will be placed. The main mode of operation in this case is arbitrary, although the sequential data processing mode is also possible. Memory space occupied by a remote record can be used for a new entry that has received the same address.

In practice, the processing of records is often produced by several fields. In this case, the advantages of direct files are practically reduced to no, since the processing of entries in them in arbitrary access is possible only by one key field.

At the same time, it is obvious that it is possible to increase the efficiency of data processing, first of all by ordering records in descending order or increase the values \u200b\u200bof a particular field. Such an ordering is carried out, as a rule, not in the source file, and in the created additionally (such converted by any key field is filed files inverted). When processing a file for several keys, you have to create an appropriate number of inverted files. Since each inverted file in reality contains the same information as the source, this approach requires large volumes of external memory.

For the rationalization of data processing, you can use index-sequential files - a set of data file and one or more index files. In the latter, the initial data itself is stored, but only numbers (indexes) of the source file entries defining the procedure for processing on a specific key. The index file is filed in sequential mode, and the data file is in direct access mode.

The file with a library organization consists of consistently organized partitions, each of which has its name and contains one or more logical records. At the beginning of the file there is a special

the service partition is the so-called table of contents that allows direct access to each data section.

Check questions and tasks

1. What data representation levels are used when describing the subject area?

2. Allow the concepts of "logical recording" and "Record field".

Expand the features of the presentation of data in RAM and PAU.

4. Give examples of linear and nonlinear storage structures.

5. Describe the types of file structures and the features of their organization.

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What is a backup copy

A backup is a copy of the working files and folders, which is created regularly or periodically and provides the ability to restore the data in case of their loss (damage, theft, random erasure). In this article, we will express our point of view about the place of posting backup of information, i.e. Reply to the question "Where?" Let everyone choose the most appropriate way to store backups. For some, the cheapness is important, for someone - maximum confidentiality.

Where the most reliable to store backup data

1. Network Storage (NAS)

Image from the official site D-Link

Benefits:

Relative device compactness.
The ability to arrange in a remote place and disguise.
RAID1 technology to protect against the failure of a hard disk.
Full control of information. The device with information is physically in your hands. Your task is only to protect the files with reliable passwords.
If you do not trust cloud services and believe that administrators browse your files, then this option for you 🙂

Disadvantages:

The probability of information loss due to equipment failure is higher than that of a cloud storage.

The most secure scheme - when the network storage is physically in a secret room, and backup copies protected by complex passwords are written on it over the network.

2.
Backup storage

Another computer

An option is similar to using NAS.

Lower fault tolerance if there is no RAID array.
Lower reliability if other people have access to the computer.
Bulkiness. The computer is usually harder to disguise than the network storage.
Higheby probability problems with network access. The computer may hang or refuse access. This happens because of the installation of updates or actions of anti-virus software.

3. External (Portable) Hard Disk

Image from the official site Western Digital

Advantages Compared to NAS:

Mobility. You can charge with you after creating a copy.

Disadvantages compared to NAS:

You can not connect to the computer network directly. Accordingly, you can not disguise in the connected state.
No protection from a hard disk failure.

4. Cloud storage.

Examples: Google Drive, Yandex.Disk, Sky.Drive

Benefits:

Easy access from anywhere in the world and accessibility 24 hours a day.
Yes, global access to NAS can also be customized, but using a cloud, the owner will be much easierget access to K. his information.
High speed access to backups.
Minimized the risk of repository failure and data loss. Cloud warehouses Google, Yandex, Microsoft are located on reliable servers and are serviced by the best IT professionals.
Protection against stealing storage. If a thieves died into the room and stole the server, a network storage and all hard drives, you can restore the working data from the cloud.
Privacy is higher than the cloud storage.

Disadvantages:

When installing an unreliable password, the mailbox can hack intruders. After that, information will fall into other people's hands, and may also be simply removed.

5.

Benefits:

Mobility and compactness. The USB carrier can be stored in a secret place.

Disadvantages:

Conducts a relatively small amount of information.
When stored outside the room there is no access to a backup.

6. DVD.

Benefits:

Mobility. Can be stored in a secret place.

Disadvantages:

Small amount of information.
Low speed of creating and restoring backups.
Fragility and short-life of media.

7. Another hard disk on the same computer.

Such a scheme is one of the easiest. However, it protects at least from a hard disk failure and from accidental deletion of files.

Benefits:

Instant access to backups.
Maximum speed of copying and restoring information.

Disadvantages:

Does not protect against theft of the computer.
Does not protect from damage to files when hacking and infected with viruses.
As a rule, access to copies is possible only from this computer.

In the article, we reviewed options that more or less average average user is available. Clear things that there are ways of reliable network storage. For example, server. And it is better - ten servers connected to a 100-gigabit Internet channel with synchronization of real-time information. But such backup protection schemes are used by providers, large corporations and the following cloudustries described above.

Perhaps it will be interesting:

9.3 Information Protection Methods

What is the protection of information?

Under information protection It is understood to ensure its safety on machine media and prohibiting unauthorized access to it. Information protection is provided:

reservation of files;
archive copying files;
restricting access to information;
application of antivirus.

Reservation of files

Reservation of files Create the creation of copies of them on the machine media and systematically update them in case of changing the files.

How to store backup data

The need for redundancy is caused by various circumstances. For example, a hard disk can be fully filled, and it will not be possible to record new information without destruction of the old. Or when operating a computer, a damage may occur or complete destruction of information on disks. This can happen for various reasons:

the impact of computer viruses;
incorrect actions or accidental destruction of files;
physical damage of the disk or hard disk drive;
intentional actions of some persons.

In this backup method, a simple copy of one or more files or file structure is obtained, that is, the directory tree with files included in them on the same or other media (disk, magnetic tape, CD, Flesh, etc.). Backups occupy the same place as the source files occupy. MS-DOS is copy, xcopy, diskcopy commands. In Norton Commander, Far, et al. - There are similar teams. Copying files, directories and disks in Windows are performed using a clipboard or other way. Reservation of files is also used when transporting files with one computer to another, if they are not combined into the network.

Archival copy files

The main feature of the archival copy of the files is the compression of files in order to reduce the archive copy of the space on the machine media. With such a reservation, one archive file is created, which is a set of one or more compressed files, from where they can be removed in its original form. The size of the compressed file is two to ten times less than the size of the original file. The degree of compression depends on the first, on the type of file, and secondly, from the archiver program. Most of all squeezed database files and text files, and less than all - binary software files (type EX and COM). The process of writing files to the archive file is called archiving (packaging), Removing files from the archive - unzipping (unpacking ), and archive file - archive .

Archive The archive file contains a table of contents, allowing you to find out which files are contained in the archive. Some archivers can create multi-volume archives.

Archiving is performed using archived software. The most common archiving programs have approximately the same features, and none of them exceeds others in all parameters: some programs work faster, others provide a better degree of file compression. Functions performed by archiver:

placing files to the archive;
removing files from the archive;
view the file contents of the archive;
forwarding files to the archive and from the archive (after sending files from the source are removed);
archiving directories;
checking the integrity of the archive;
restoration of damaged archives;
protection of archives with password.

Restricting access to information

Under restricting access to information It is understood to eliminate unauthorized access to it. It is provided by software and technical means:

application passwords;
file encryption;
destruction files after removing them;
using electronic keys;
making a computer in a special protected execution.

Passwords

Passwords are used to identify users and delimit them rights on the computer network and to limit the access of users working on a single computer to various logical disks, directories and files. Various levels of password protection can be installed. For example, reading the disk is possible without entering a password, and to change, delete or save a file on a secure disk password is needed. Password protection files does not imply compulsory encryption.

Encryption

Encryption– Such a data conversion, as a result of which they can only be read using the key. Encryption is engaged in science, which is called cryptography. In cryptography, any unencrypted text is called open text, and encrypted data called encrypted text. Modern encryption algorithms are a complicated mathematical task, to solve which, without knowledge of the decrypting key, you need to perform a giant amount of computing and get an answer, possibly in a few years.

Disc protection

When you turn on the protection of the disks from an unauthorized recording to the memory, a resident module is loaded, which displays a message about an entry attempt. In response, the user must allow or prohibit the record. This type of protection reduces the likelihood of information destruction due to erroneous actions of the user, and also allows you to detect possible actions of viruses.

Displaying (visualization) The reading or writing process to the disk draws the user's attention to this process so that the user can estimate the legality of access to the disk.