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How to Use Disk Staging to Manage Backup Data

The following list describes how you can use staging to manage backup data.

• Using disk staging you can back up data to file system devices (FSD) that are used as a temporary staging area. A staging job can divide your backup job into several subjobs that run simultaneously. Disk staging lets you use simultaneous streaming to send multiple streams of data to the FSD. Since the data is split among several different streams, backup jobs with simultaneous streaming enabled can be completed significantly faster than regular backup jobs.
• You can then migrate (copy) the data from the FSD to a final storage media (or from disk to tape). As a result, the tape drive can be kept streaming, thereby minimizing the shoeshine effect (starting, stopping, and repositioning the tape), and increasing both the life expectancy and efficiency of the tape drive. While the backup image is still on the FSD, data can be restored directly from the FSD. The restore time is significantly reduced because restoring data from disk is generally faster than restoring from a tape (no delays due to tape load and seek latency).

  Note: When you back up data from a disk staging location to the final destination, you are then able to perform a Double Tape Copy. Double Tape Copy lets you migrate (copy) the data to two destinations simultaneously which writes to the destinations in parallel to save time. To use this feature, it is required to configure a Disk Staging device to your environment. See Device Configuration for more details.

  To ensure that the migration job continues when one of the devices become unavailable, you can set a timeout value for additional backup media to continue the migration job in another device. If you do not set a timeout value, then the data migration job fails after the first backup media timeout completes. For more details about setting the timeout value, see Backup Manager Backup Media Options.

• During the backup-to-FSD process, if the FSD gets full or reaches the specified maximum threshold, Arcserve Backup lets you create makeup jobs which would then back up the data directly to the final destination after the staging backup job fails. This increases the success rate of backups. In addition, if there are any errors during the copy-to-final destination process, Arcserve Backup lets you create makeup jobs.

  Note: Under disk full conditions, the makeup job created to back up the data to tape will always try to use a blank tape or a media from a scratch set. It will never try to append to an existing media.

• The backup images are kept on the FSD until the retention time expires (as determined by the specified purge policy). At that time, Arcserve Backup automatically purges the data from the FSD, and reclaims disk space so that backups can continue.
• For rotation jobs or GFS rotation jobs, Arcserve Backup lets you specify policies that disable staging for any particular day. This feature is helpful in situations where the FSD is full, is scheduled for maintenance, or has a problem.

More information:

How to Use Tape Staging to Manage Backup Operations