Tape Backup

Tape Backup

The system of network backup consists of hardware and software components.
Hardware components are serving the purpose of writing and storing backups, providing a recovery source anytime it is needed.
Entire network backup logic is concentrated in software components and is implemented by them. They are responsible for management of devices, backup and data recovery processes, scheduling and also additional service functions.

Backup system hardware components

In order to choose hardware correctly, one needs to determine the media, which will optimally meet the requirements faced by the system, as well as the controller for this media.

Hard disk drives, magneto-optical disk drives and tape drives are commonly used as storage media.

A hard or magneto-optical disk would be suitable for one-time backup of a small-sized data array. A barrier for using hard drives is their high cost. If we’re talking about choosing a proper hardware for carrying out full backups, and in automatic mode, we should prefer tape drives: they provide the same recovery speed as magneto-optical drives, while showing a better write speed. The cost of data storage on magnet tape is the lowest comparing to that of other media. Therefore, the most efficient and reasonable storage for large volumes of data are magnet tape drives.

For working with magnet tapes, backup systems make use of so-called autochanger tape drives, or tape libraries.

Tape library consists of two functional devices:

- read/write device, or streamer, which is used for writing information to the tape and reading from it. At any given moment of time a streamer is capable of working with only one tape cassette;
- cassette autochanger device, or robot, consisting of a cassette stack and a mechanism, which inserts the requested cassette into the streamer and ejects it afterwards.

Usually tape library vendors only make robots and integrate them with streamers made by other manufacturers, selling resultant products under their trademark. All streamers currently manufactured implement read/write technologies providing high density of stored information, and as a result large capacity and high reliability of storage.

Streamers based on DLT technology, which is rapidly developing lately, are quite common now. The features of this technology are high write density, fast data transfer and reliability. All manufacturers of tape libraries generally use DLT streamers in their latest models. Other quite widespread standards of magnet data storage are DDS-2 and DDS-3.