Unix Backup and Recovery

VOB Backup and Recovery Procedures

A VOB (Versioned Object Base) is a data repository for a directory tree. A VOB is implemented as a standard directory tree, whose top-level directory is termed the VOB storage directory. The directory contains files and subdirectories. The VOB storage area is recognizable by its vbs suffix.

The VOB must be activated on the host by mounting it as a filesystem of type MVFS (ClearCase multiversion filesystem type). See the ClearCase mount reference page for more information. As mentioned earlier, most sites leave the backup/restore of private VOBs to the individual owner, but if the site wants to include private VOBs in their normal backup, the following procedures can apply to private VOBs as well.

VOB Backup Strategies

The general VOB backup strategy is to follow a three-step process:

1. Make the VOB quiescent.

2. Back up the storage directory.

3. Reactivate the VOB.

This section discusses the various ways in which this can be done.

Common strategies for doing a VOB backup include (but are not limited to): standard and snapshot (the two most common), disk backup, and the use of mirrors. Since the main thrust is the backing up of the physical storage directory, there are many ways this can be accomplished, including the use of commercial tools.

Standard strategy

The standard backup procedure is to “lock” the VOB, thereby ensuring that it is unavailable to other processes during the backup. It is extremely important that the VOB remain locked during the backup process; ...