Deduplication Data Consistency

In the CommCell environment, if deduplication is enabled for any storage policy, the following three components need to be synchronized:

• CommServe Database

• Deduplication Database (DDB)

• Data blocks on Disk

There might be circumstances where these three components can be out-of-sync. These scenarios could be:

• CommServe disaster recovery (DR) restore

  Restoring from previous DR backup might cause both CommServe database and the DDB out-of-sync and might result in backup failures.

• Unplanned shut down of the MediaAgent hosting the DDB

  When backups are running, the signatures of the backups are stored in the DDB. If there was unplanned shutdown of the MediaAgent hosting that DDB, the DDB and disk will become out-of-sync and result in backup failures.

• Backup disk has unreadable or missing data

  The DDB pointing to data blocks that are unreadable or missing, might result in restore or Auxiliary Copy job failures.

To keep these three components synchronized:

• Use Resynchronizing the Deduplication Database, if the CommServe database and DDBs are out-of-sync and you need to reconcile inconsistencies between these databases.

• Use Verifying the Deduplicated Data, if the DDB, disk, and the CommServe database are out-of-sync for the deduplicated backup jobs.