Archival storage of electronic documents: problems and solutions. Storage of hard disks and magnetic tapes Storage media storage
It is convenient to use external media to store and transfer information from one computer to another. Optical disks (CD, DVD, Blu-Ray), flash drives (flash drives) and external hard drives are most often used as storage media. In this article we will analyze the types of external storage media and answer the question "Where to store data?"
Now optical discs are gradually fading into the background and this is understandable. Optical discs can record relatively little information. Also, the usability of an optical disc leaves much to be desired, besides, discs can be easily damaged, scratched, which leads to a loss of disc readability. However, for long-term storage of media information (movies, music), optical discs are suitable like no other external media. All media centers and video players still play optical discs.
Flash drives
Flash drives or in a simple way "flash drive" is now in the greatest demand among users. Its small size and impressive amount of memory (up to 64GB and more) can be used for various purposes. Most often, flash drives are connected to a computer or media center via a USB port. A distinctive feature of flash drives is the high speed of reading and writing. The flash drive has a plastic case, inside which an electronic board with a memory chip is placed.
USB sticks
A type of flash drive can be attributed to memory cards, which with a card reader are a full-fledged USB flash drive. The convenience of using such a tandem allows you to store significant amounts of information on various memory cards, which will take up a minimum of space. In addition, you can always read the memory card of your smartphone, camera.
Flash drives are convenient to use in everyday life - transfer documents, save and copy various files, watch videos and listen to music.
external HDs
External hard drives are technically a hard drive housed in a compact enclosure with a USB adapter and anti-vibration system. As you know, hard drives have impressive amounts of disk space, which, coupled with mobility, makes them very attractive. You can store all your video and audio collection on an external hard drive. However, the external hard drive requires more power for optimal performance. A single USB connector cannot provide adequate power. This is why there is a dual USB cable on external hard drives. External hard drives are very small in size and can easily fit in a regular pocket.
HDD boxes
There are HDD boxes designed to be used as a storage medium for a conventional hard disk drive (HDD). Such boxes are a box with a USB controller, to which the simplest hard drives of a stationary computer are connected.
Thus, you can easily transfer information directly from your computer's hard drive directly, without additional copying and pasting. This option will be much cheaper than buying an external hard drive, especially if you need to transfer almost the entire hard drive partition to another computer.
For the normal operation of any business, prompt access and reliable storage of information is important. Technical failures, update errors, cyberattacks and other force majeures, in turn, can lead to data loss, which means financial losses, up to the complete collapse of the company.
We have already written about the deplorable examples of large companies and the importance of backups in the article on 3 strategies
Every day it becomes clearer that backing up information (backup) on the server is the number one necessity for any business. And the good news is that it is possible to restore the entire archive of events, documents and programs with the right choice of backup methods.
In the event of an emergency, it is the backup copy of all data that provides full online access to all information stored on damaged media.
To copy information from digital media, different methods of backup and storage are used - these are backup and data redundancy. They are different, but sometimes they can be applied at the same time.
Data redundancy allows files to be restored immediately after a failure in the event of a failure. The principle of operation is that when access to a file is lost, it is replaced by its copy. This helps to avoid downtime for the site or application and allows the server administrator to return the system to its original working state.
It would seem an optimal solution, but it has a number of significant drawbacks. In the event of system failures of the entire server, all data may be lost. In addition, every operation on the system affects the copy that is saved. So, in the case of malicious operations in the system, errors will remain in all subsequent copies of the data.
In the case of backup, the data is returned to its original state, and it can be restored for any period of time, depending on the depth of the backup.
Backing up critical information, even in the event of a failure of an individual application, an entire machine, or the loss of individual data, allows you to redeploy, restore or access this information. The downside of Backup, in contrast to the redundancy approach, is that it takes time to restore information and the equipment is idle. But the data is accurately stored and access to them is guaranteed, and with those parameters and from the moment when the user needs it.
The ideal option for storing valuable information is automatic backup to a remote server, which is independent of external influences and is regularly moderated by administrators. At SmileServer, in each tariff we offer backup and storage of our clients' data on servers in Germany, which ensures their safety and security in case of any technological failures.
Backup strategy on the server
The best strategy for ensuring the safety of data and the smooth operation of user resources is to combine backup technologies and data redundancy. If one host fails, the machine will continue to work without failures, since the migration mechanism will work, and thanks to the backup technology, all files will be restored from the hard disk.
A number of commands such as cp and rsync can be used manually to set up a backup. But to automate the copying process, this approach requires the creation of separate scripts, which is difficult and not always effective. For business tasks, backup is carried out using special tools and utilities, such as BackupPC, Bacula and Duplicity, which we propose to consider in more detail.
Automated backup solutions
Special comprehensive backup solutions make the procedure easy and do not require active participation and multi-level configuration from administrators.
BackupPC
The solution is applicable for both Windows and Linux, it is installed on a dedicated server or VPS, which acts as a backup server. This server then downloads the custom files. All the necessary packages are installed on one server, and you only need to configure access to the disk via the protocol or SSH. On virtual Smile Servers, BackupPC SSH keys can be deployed without additional software.
Bacula
A versatile and technically sophisticated client-server host backup program. It sets up each backup task as a separate Job. This approach allows fine tuning, connecting multiple clients to one repository, changing copying schemes, and expanding functions using additional modules.
Duplicity
It is a true alternative to all existing backup tools. The main difference of this software solution is the use of GPG encryption when storing information, which increases the security of data storage.
The main advantage when using GPG encryption for backups is that the data is not stored in plain text. Only the owner of the encryption key can have access to them.
Block backup
This type of backup is also called "imaging". The technology allows you to copy and restore data from entire devices. If during standard backup copies of individual files are formed at the file system level, then during image creation the data is copied in blocks without splitting into files.
The main advantage of block backups is high speed. The point is that file-based backups re-initiate the process for each individual file, while block copying of files has much more than one for each block.
All of these technologies and numerous ways to set up self-service data backups will help you avoid the disaster in the form of irrecoverable loss of valuable information or data of your customers.
When placing information on external media (thus, we are talking about the physical level of its storage), the unit of information is a physical record - a section of the media on which one or more logical records are located. The named integral collection of homogeneous information recorded on an external medium is called a file. In fact, the file is the main unit of data storage on B3Y, and it is with the files that these or those transformation operations are performed (adding data, correcting them, etc.).
The following types of file data structures are used to store data on external media.
sequential;
index-sequential;
library.
Data in file structures can be accessed in two ways - sequential or arbitrary. With sequential access (processing mode), the file records are transferred from the OVC to the RAM in the order in which they are located on the media. In contrast, in random access mode, they can be retrieved from a file as required by a specific application program.
In sequential files, records are arranged on the medium in the order in which they are received. By means of a buffer, they are all sequentially transferred to the main memory for processing.
Backup
An arbitrary mode of processing is impossible here, since in order to search for a record by any criterion, it is necessary to carry out a sequential enumeration of all records. Deleted records are physically excluded by creating a new file.
An example is simple text files (ASCII files). They are made up of strings of characters, with each line terminated with two special characters: carriage return (CR) and line feed (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 relationship between the recording key and its location on the medium. When a logical record is written to a file, the conversion or mapping of the record key to the memory address at which it will be located is performed. The main mode of operation in this case is arbitrary, although a sequential mode of data processing is also possible. The memory space occupied by the deleted entry can be used for a new entry at the same address.
In practice, processing of records is often carried out in several fields. In this case, the advantages of direct files are practically negated, since the processing of records in them in random access mode is possible only for 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 the records in descending or ascending order of the values of a particular field. Such ordering is carried out, as a rule, not in the original file, but in an additionally created one (such a file transformed by some key field is called inverted). When processing a file using several keys, you have to create the corresponding number of inverted files. Since each inverted file actually contains the same information as the original, this approach requires a lot of external memory.
To rationalize data processing, you can use index-sequential files - a collection of a data file and one or more index files. In the latter, not the original data themselves are stored, but only the numbers (indices) of the records of the source file, which determine the order of its processing according to a certain key. The index file is processed in sequential mode, and the data file is processed in direct access mode.
A library organization file consists of sequentially organized sections, each with a different name and containing one or more logical entries. At the beginning of the file there is a special
service section - the so-called table of contents, which allows direct access to each data section.
Control questions and tasks
1. What levels of data presentation are used to describe the subject area?
2. Give a definition of the concepts "logical record" and "record field".
Expand the features of data representation in RAM and OVC.
4. Give examples of linear and non-linear data storage structures.
5. Describe the types of file structures and features of their organization.
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What is a backup
A backup copy is a copy of working files and folders that is created regularly or periodically and provides an opportunity to restore data in case of loss (damage, theft, accidental erasure). In this article, we will express our point of view regarding the location of the backup copies of information, i.e. Let's answer the question "Where?" Let everyone choose the most suitable way of storing backups. For some, the low cost of implementation is important, for others - maximum confidentiality.
Where is the safest place to store data backups?
1. Network Attached Storage (NAS)
Image from the official website of D-Link
Advantages:
- Relative compactness of the device.
The ability to locate in a remote location and disguise.
- RAID1 technology to protect against hard drive failure.
- Full control over information. A device with information physically in your hands. Your only task is to protect files with strong passwords.
If you do not trust cloud services and believe that administrators view your files, then this option is for you 🙂
Disadvantages:
- The likelihood of information loss due to hardware failure is higher than that of cloud storage.
The safest scheme is when the NAS is physically located in a secret room, and backups protected by complex passwords are written to it over the network.
2.
Backup storage
Another computer
The option is similar to using a NAS.
- Lower fault tolerance if there is no RAID array.
- Lower reliability if other people have access to the computer.
- Bulky. A computer is generally more difficult to disguise than NAS.
- Higher likelihood of network access problems. The computer may freeze or be denied access. This happens due to the installation of updates or the actions of antivirus software.
3. External (portable) hard drive
Image from the official website of Western Digital
Advantages over NAS:
- Mobility. You can take it with you after making a copy.
Disadvantages compared to NAS:
- Cannot be directly connected to a computer network. Accordingly, it cannot be masked in the connected state.
- No protection against hard drive failure.
4. Cloud storage.
Examples: Google Drive, Yandex.Disk, Sky.Drive
Advantages:
- Ease of access from anywhere in the world and availability 24 hours a day.
Yes, global access to the NAS can also be configured, but using the cloud, the owner will have much simpler get access to his information. - High speed access to backups.
- The risk of storage failure and data loss is minimized. Cloud storages Google, Yandex, Microsoft are located on reliable servers and maintained by the best IT specialists.
- Storage theft protection. If thieves sneaked into the room and stole the server, network storage and all hard drives, you can restore production data from the cloud.
- Privacy is higher than cloud storage.
Disadvantages:
- When a weak password is set, the mailbox can be hacked by hackers. After that, the information will fall into the wrong hands, and can also be simply deleted.
5.
Advantages:
- Mobility and compactness. The USB stick can be kept in a secret place.
Disadvantages:
- Contains a relatively small amount of information.
- When stored outside the premises, there is no access to the backup.
6. DVD
Advantages:
- Mobility. Can be kept secret.
Disadvantages:
- Little information.
- Low speed of creating and restoring backups.
- Fragility and fragility of carriers.
7. Another hard drive on the same computer.
This scheme is one of the simplest. However, it protects at least from hard drive failure and from accidental deletion of files.
Advantages:
- Instant access to backups.
- Maximum speed of creating a copy and restoring information.
Disadvantages:
- Doesn't protect against computer theft.
- Does not protect against file corruption during hacking and virus infection.
- Typically, copies can only be accessed from this computer.
In the article, we examined options that are more or less available to the average user... It is clear that there are ways more reliable than network storage. For example, a server. Better yet, ten servers connected to a 100-gigabit Internet channel with information synchronization in real time. But such backup protection schemes are used by providers, large corporations and the cloud storage services described above.
It might be interesting:
9.3 Information security methods
What is information protection?
Under protection of information means ensuring its safety on machine media and prohibiting unauthorized access to it. Information protection is provided:
- backing up files;
- archiving files;
- restriction of access to information;
- the use of antivirus tools.
File backup
Backing up files call the creation of their copies on machine storage media and their systematic updating in case of changes in the backup files.
How to properly back up your data
The need for redundancy is caused by various circumstances. For example, the hard disk can be completely full, and it will not be possible to write new information on it without destroying the old one. Or, during the operation of the computer, damage or complete destruction of information on the disks can occur. This can happen for various reasons:
- exposure to computer viruses;
- incorrect actions or accidental destruction of files;
- physical damage to the disk or hard disk drive;
- deliberate actions of some persons.
In this method of backup, a simple copy of one or more files or file structure is obtained, that is, a directory tree with files included in them on the same or another storage medium (disk, magnetic tape, CD, flesh, etc.). Backups take up the same amount of space as the original files. In MS-DOS, these are the COPY, XCOPY, DISKCOPY commands. Norton Commander, FAR, etc. have similar commands. Copying files, directories and disks in Windows is performed using the clipboard or in another way. File backup is also used when transporting files from one computer to another, if they are not connected to a network.
Back up files
The main feature of the archive copying of files is the compression of files in order to reduce the space occupied by the archive copy on a computer storage medium. This backup creates a single archive file, which is a collection of one or more compressed files, from where they can be retrieved in their original form. The size of the compressed file is two to ten times smaller than the size of the original file. The compression ratio depends, firstly, on the file type, and secondly, on the archiving program. Database files and text files are compressed the most, and binary program files (such as EXE and COM) are the least compressed. The process of writing files to an archive file is called archiving (packing), extracting files from an archive - unzipping (unpacking ), and the archive file is archive .
Archive The archive file contains a table of contents that lets you know what files are in the archive. Some archivers can create multivolume archives.
Archiving is performed using archiving programs. The most common archiving programs have approximately the same capabilities, and none of them surpasses others in all respects: some programs run faster, others provide better file compression. Functions performed by the archiver:
- placing files in the archive;
- extracting files from the archive;
- viewing the contents of the archive;
- transferring files to and from the archive (after transferring files from the source are deleted);
- archiving catalogs;
- checking the integrity of the archive;
- recovery of damaged archives;
- protection of archives with a password.
Restricting access to information
Under restricting access to information the exclusion of unauthorized access to it is understood. It is provided by software and hardware:
- application passwords;
- file encryption;
- destruction files after deleting them;
- usage electronic keys;
- computer manufacturing in a special protected execution.
Passwords
Passwords are used to identify users and differentiate their rights in a computer network and to restrict access of users working on one computer to various logical drives, directories and files. Different levels of password protection can be set. For example, you can read a disk without entering a password, but you need a password to change, delete, or save a file on a secure disk. Password protection of files does not imply their mandatory encryption.
Encryption
Encryption– such a transformation of data, as a result of which they can only be read using the key. Encryption is dealt with by a science called cryptography... In cryptography, any plain text is called open text, and the encrypted data is called encrypted text. Modern encryption algorithms are a complex mathematical problem that requires a huge amount of computation without knowing the decryption key and getting an answer, possibly in a few years.
Disk protection
When disks are protected against unauthorized writing, a resident module is loaded into memory, which displays a message about an attempt to write on the screen. In response, the user must allow or deny recording. 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 (visualizing) the process of reading or writing to a disk draws the user's attention to this process so that the user can assess the legality of access to the disk.
Information storage was a very important moment in the development of mankind. People are constantly faced with a situation where information storage devices become obsolete along with its content. In the zero years, humanity transferred video and audio materials from audio cassettes and VHS to CDs, flash cards. seemed like an untouchable archive of data. Only after a while it became clear that if the film on the cassette does not dry, this does not mean that the information will be preserved and will exist forever: someone scratches disks, someone loses flash drives, and hard drives generally dry out over time. Therefore, leading software developers around the world have taken up the task of safe and long-term storage of information.
And if you create an archive of the necessary data on a hard drive, then third-party access to this data depends solely on the owner of the media, on how reliable the storage location will be chosen.
Storage options popular today
- ... This storage option is suitable for those who do not have permanent access to the network and those who worry that data will be safely hidden from third-party tampering with the content. Choosing a reliable external creation of an archive of documents, photos or videos, you should not use a local scratch disk, since there is a possibility of failure of such a device - under constant load, the screw may not last long, the OS will crash or it will burn out. For long-term storage, it is better to use SSD usb disks, which have an impressive amount of storage, a well-thought-out algorithm for managing file recording cells. And they won't take up much space in the safe.
Before sending a good portion of information for storage for a long time, it must be properly preserved.
For this, many utilities have been developed, the most common of which is WinRAR
This program creates archives for long-term storage of data. Plus, it contains a function for compressing the file structure. With it, it's easy to organize your files. Such training is carried out regardless of the device on which the data is stored. Even if it means storing information on a remote server, then uploading one archive is much easier than uploading dozens of small or one impressive file.
After archiving the data, you need to prepare a device for storing information, which will host the archive data. ...
First of all, the hard drive needs to be formatted and defragmented.Formatting is comparable to the situation when putting things in a bag, you shake it out, clean it.
Formatting does the same thing, only with the hard drive. When formatting, you will be offered several options - how to structure the files. NTFS or FAT32. It is preferable to choose the second one (if there are no startup files or OS files on the screw).
Defragmentation in the physical sense transfers the filled memory cells to the beginning of the disk, thereby leaving room for the propeller to overclock when reading information in the future.
- Flash drive. Flash drives are a convenient storage device. And, according to most, cheap. The advantages are that the use of FLASH is available on almost all modern devices - 90% of equipment for data processing around the world is equipped with USB ports - from car radios to TVs.
The process of preparing the archive files and the drive itself is no different from the preparation described in paragraph 1.
The downside of this storage device is that it is small and can easily be lost. Such external storage devices are easy to transport or transfer from one user to another without the need for electronics. Types of flash drives differ in two main parameters - the presence of a shockproof shell and the data transfer rate (2.0 or 3.0).
- CD and DVD. Long-term storage in a specially designated place where they are not threatened with mechanical damage is an acceptable option for storing information. With the materials recorded on them, nothing will happen over time. But in order to write data to this kind of media, it is necessary to use utilities. In the latest operating systems, the recording function is implemented at a basic level.
New ways of storing information appear every year. And everyone can choose the one that is convenient for him. It is better to store photos in electronic form on the cloud - these are several interconnected servers that are specifically designed for this.
Cloud storage service is provided by most of the popular social networks, giant IT corporations. It is not always convenient to store photos on external media when you need constant access to them from various places.
Often, information storage facilities are provided remotely, for example, by Yandex, whose service is called Yandex.Disk.There are many similar services, but each of them has its drawbacks. Every developer or company in general has to make money, so nothing is absolutely free.
The well-known service DropBox provides convenient access to the server around the clock at the user's request, but at the same time limits the space that the user can useProvided that the user of this service attracts third parties, his disk space increases many times over.
Modern means of information storage cannot provide comfortable access to the necessary data for a long time.
Anything can happen to sites, servers, so the idea of storing data on external devices should not be abandoned and the choice of a hard disk or flash drive should be deliberate and balanced.M-Disk
Storing information is a guarantee that future generations will change the current state of society for the better. To make the future better, you need to preserve the present. The developers of one of the projects have created a fundamentally new medium that looks like an ordinary dvd disc. Its fundamental difference lies in the fact that information can be stored on it for more than a thousand years. Even the most reliable hard drives cannot boast such a temporary warranty. Such a long period of time will provide the ability to analyze the data several centuries later without loss of quality. It is practiced in modern society to create time capsules, where the M-disk is invested. Now such discs are available for sale and its average price is three dollars. Not a single computer today will give confidence that the information recorded on it will last ten centuries.
In conclusion, we can say that none of the methods guarantees the eternal safety of information, and justifies the hopes for the infinitely long use of devices, but science is moving and allows us to create more and more new developments in this area. It doesn't matter to preserve history and pass on knowledge to future generations, store photos, paintings, songs or digital passwords. The main thing is to store archives on such devices so that the information can be used in the future.
Summary list of storage options
Let us summarize so that you can make the right choice of a device or method of storing information. Let's go through the agreed points again:
- HDD; - roomy, permanent offline access is possible;
- SSD; - durable, constant access, a serious amount of information;
- Flash drive; - durable, but fragile and there is a high risk of losing this device;
- M-DISK; - Serious amount of data, reasonable price, durable.
- Of all the cloud storage services, the following are the most popular:
- DropBox;
- Yandex.Disk;
- Radikal (for storing photos and graphics)
Google (GDocuments is especially geared towards storing text files and spreadsheets)
When choosing a device for long-term data storage, you need to determine the type of this data. Recommendations on which files are best stored where.
- It is better to store archives of family photos on disks that are not intended for rewriting, because there are often cases when, by pure chance, very necessary photos are erased. Every user has encountered this. It is not possible to recover data from CD or DVD-RW. These are materials that cannot be restored under any circumstances - it is impossible to download photographs of the nineteenth century on the Internet, if only no one posted them there at the time of creation. It is better to store such claims “under the pillow” or in the same place where the photo albums are kept.
- Documents are files that are much smaller than media, so they are written to a flash card, on which rewriting using auxiliary programs is prohibited. Working from a flash drive is much more convenient than from an optical disc, regardless of its format. Just do not forget about mechanical damage to the device, which can permanently destroy the information recorded on the carrier.
- It is more convenient to store your music or video collection on your hard drive, since this is the file format that is accessed regularly. It is inconvenient to constantly connect an external device, and the files on the screw are freely available around the clock.
- It is better to store the materials that users use on the cloud so that they can be accessed online by access points located at a distance from each other. Keep in mind that when disconnecting from the network at the time of editing files, a backup copy is regularly created, which is restored when the connection is resumed. For users, mandatory registration in such services becomes a negative argument. Few people like to leave contact information in order to use this or that service.
WATCH THE VIDEO
Now you know all the ways to store information. Ask questions to specialists.
Where are the bytes, Zin?
Network folklore
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The choice of a storage device in 2017 is a very, very controversial topic. Gone are the days when you could only choose from small hard drives or CDs (for the majors, yeah): today the range of storage solutions is greater than ever.To begin with, let's decide on why we, in fact, store something - in the era of the Internet? When is everything “in heaven” in the clouds?
First of all, today we are buried under an abundance of information. Petabytes of necessary and unnecessary (more often) data fall on us like an avalanche, and here we are not even talking about news, but about physical data: photographs, a huge amount of pirated and not so much music and films. This also includes applications "that will come in handy someday"; films that have been watched once, "maybe I'll watch the second time" ... Not everyone is deleted, right? The question is where to store all this.
Then - "backups". Again, it is no secret to anyone that modern and cheapest in terms of the price per megabyte factor hard drives (traditional, "pancake") suffer from poor quality. For example, I have set up an almost complete daily mirroring of the system hard disk and the data disk to models that are identical in size. Why? Precisely because any Winchester can fly into blue skies at any time and in any place.
Alas, today's consumer society recognizes only that which is cheap, does not last long and dies quickly. Therefore, reliable hard drives of the late 1990s (and I still have a 1998 IBM HDD - like a rarity!) Have remained legends in which modern 128-bit people no longer believe. On the other hand, at the turn of the century, I personally lost two Quantum "hard drives", so the reliability depended on the manufacturer as well. By the way, the heirs of Quantum in the nth generation are now known under the name Seagate. Information is just for thought.
Reliable storage of information is a problem familiar to most modern enterprises, when resolving it, the question always arises: how to get a high-quality result with relatively low costs? Storing documents in electronic form ensures not only their safety, but also their unhindered availability in real time.
For long-term and reliable storage of archival information in electronic form, various types of information carriers are used. The main requirement for such media is the exclusion of the possibility of physically making changes to the archived data or deleting them. The information carrier must provide a one-time write and at the same time be able to read information multiple times. These requirements are met by the information carrier of the WORM type - Write Once, Read Many (write once, read many times). Other basic requirements for storage media include durability and maximum storage capacity for archived data.
Hard drives.
The use of hard disks makes it possible to organize the so-called "online" storage of archived data, which provides constant on-line access to archived documents. The core of such storage is a tiered archive storage architecture, in which frequently requested archive data is stored on "fast" hard drives with an external Fiber Channel (FC) or Serial Attached SCSI (SAS) interface, while rarely requested archive data is stored on "slow" hard drives. drives with external interface Serial ATA (SATA) and NL-SAS.
There is an opinion that backup systems are a burden for the IT budget, and for the IT department, so to speak, an extra headache. But ... Manufacturers of data storage systems (DSS) on hard drives of all levels still recommend using tape backup systems as part of such solutions, with the help of which a copy of data is created, from which, in the event of a storage failure, it will be possible to restore data.
Tape media.
The main purpose of tape media is to create backups of operational data (backup). On the basis of tape media, you can also organize archival storage of information. Tape solutions provide near-line access to archived information. The core of this solution is a robotic tape drive. Today, the volume of data storage on a single tape medium in the LTO-5 format is 1.5 TB (3 TB with the ability to compress data). Therefore, data storage systems on tape media are used to reliably store information in large amounts of archived data. These solutions also have a number of serious disadvantages. Tapes are demagnetized, torn, it is necessary to constantly rewind the tape in cartridges, it takes a lot of time to find a specific file while the tape is rewound in the cartridge to the desired place, the fragility of the media forces periodically transferring data from the old tape to the new tape. When organizing off-line storage, cartridges with archived data must be stored in rooms with certain environmental requirements or in specialized cabinets.
Optical media.
To organize long-term storage of archived data, it is necessary to use optical drives. Such drives ensure that all requirements for archival storage and archival data storage are met. High reliability, long periods of storage of archived data, contactless work with media, authenticity and immutability of archived data, fast random access to archived data, high capacity of optical media, organization of off-line storage of archived data are important parameters when choosing in favor of optical media.
By far the most popular optical recording format is Blu-ray, which provides high archiving densities of up to 100 GB per optical media. Hardware support for WORM allows you to store archived data recorded on optical media, which cannot be deleted or changed later. And the "open" recording format of the UDF type allows reading archived information in any device that supports working with such optical media. The main task is to store rarely requested and unchanged archive data. Practice shows that the volume of such data is about 80% of the total volume of data stored on the operational (on-line) storage. At the same time, 20% of this archived data will never be in demand. By sending such data to archive storage based on optical media, the Customer can free up to 80% of the storage volume on the online storage, which will entail a reduction in the volume and size of the backup "window".
Optical media solutions provide near-line access to archived information. The volume of storage of archived data in a drive on optical media and the number of reading devices are determined in accordance with the terms of reference. Various types of building archival solutions are supported, up to the "mirroring" of archive data between geographically distributed drives on optical media. Contactless work with optical media eliminates the possibility of damage to the working surfaces of optical media. Provides backward compatibility with previous types of optical media such as CD / DVD. When organizing archival data storage on the basis of an optical drive, you do not need to create backup copies of this data.
Advantages and disadvantages
Hard drives
- Online access to archived information
- Arbitrary access to archived information
- The popularity of the solution
- High power consumption
- The high cost of the solution
- I want to back up archived data
- Minimum "terms" of life (maximum 3 years)
- If the mechanical part of the hard disk fails, it is almost impossible to recover the data.
- Not intended for off-line storage
Tape media
- Large volumes of archived data storage
- High speed of recording information on tape media
- Low power consumption
- High total cost of ownership
- Minimum "terms" of life (on average up to 5 years)
- "Closed" format for recording information on tape media
- Low read access time (minimum 5 min)
- Loss of information when exposed to electromagnetic radiation
- Possibility of mechanical damage (belt breakage)
Optical media
- Non-volatility of optical media
- The storage period of archived information is from 50 years
- Hardware WORM Support (Archive Immutability)
- The ability to organize off-line storage of archived data
- "Open" recording format (UDF) on optical media
- Low total cost of ownership
- Low power consumption
Conclusion
Most experts in the field of building archival solutions agree that for archival storage of information with the possibility of online access to it, it is best to use a multi-tier structure of archival data storage. The main criterion in choosing a solution should not be cheapness, but the mechanism for storing and protecting archived data, which is implemented in this solution. Before making the final choice, it is necessary to check all hardware and software for compatibility.