Virtual tape library implementation, and development

Virtual Tape Library as the rise in recent years, many backup disk (Backup to Disk) solutions, most importantly, it is changing the traditional pattern of market data backup and protection of user mode.

Virtual tape libraries to achieve three main ways

Currently on the market in accordance with different architecture virtual tape libraries, can be divided into three types: software-based backup (D2D), application server type (VTL Appliance), a special type of smart (Intelligent High preformance VTL) *

• backup software-based virtual tape library (s Ⅰ on behalf of the D2D)

Tape libraries direct simulation software is installed on the server backup, server backup several file system partition that emulates tape libraries, so the backup software to use a tape library system disk file.

Within the program, a backup disk exposed to the host operating system, basically, is still "online." At the user, the data line must remain secure. For example, if the backup server is unfortunately infected, the virus can be completely destroyed on-line data on the disk, whereas damage to the backup data on disk arrays.

In addition, the program takes the host resources, limited performance.

This program is more than by the backup management software as a functional module to offer relatively inexpensive. However, subject to the file system, then the application, I / O performance and data security has certain limitations.

Therefore, the program specifically for cache back up - which is the first backup to disk, then back to the server if not busy moving to a physical tape library.



• Application Server class virtual tape library program (Ⅱ generation)

This program is really another library virtual tape software program: through a virtual tape library management software is installed on a separate dedicated server (usually a PC server) where the server and disk storage devices connected to a simulation of a tape library.

In this way, a backup server or other applications via FC or SCSI host with a dedicated server connection, then a dedicated server and disk storage systems associated with the expression for virtual tape library (VTL).

And backup software-based virtual tape library program different is that the backup server, or application server to a dedicated server and disk array as a tape library, to achieve a virtual tape library device host and the separation of physical and logical devices. Under such a program hosted on a virtual tape library to read and write mode is the data block (Block-Level) to read and write, read and write than other types of backup software, fast, and will not be back-up data from the host side generated from the host and virus removal operation does not affect the backup data.

Within the program, the virtual tape media? Logical disk volumes, the sector is no longer format of the operating system, but together with naked and tape media ("raw disk"), last backup data is stored in sequence for Byte Byte, the physical layer to reach the disk read and write linear, and to prevent fragment file system problems, fully utilizing high-speed disk device I / O performance.

Lack of such programs need to use a PC with a certain ability to expand the server as a virtual tape library manager, optimize system is lower, while the control structure using a PC server, inefficient, PC other servers and disk arrays that are connected with the management is not uniform, not a single structure, but also prone to back-end PC servers and storage that are not compatible. It seem like the new technology has turn The straight library knocks the analogue.

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