Data Verification of Deduplicated Data

Verification of Deduplication Database

(Recommended)

Verifies only the unique data blocks and completes an integrity check on the disk against the data on the DDB.

For example, if the DDB has 1 to 10 unique data blocks and they are located on disk location X, the process verifies whether these data blocks are available in that location and are completely valid and readable.

Use this option for a complete verification of data blocks on the disk. It identifies unreadable or inaccessible data blocks so that new backups refer only to valid data blocks.

This option does not ensure that the existing backup jobs are restorable.

Full and Incremental Data Verification Job

Quick Verification of Deduplication Database

• Verifies the existence of unique data blocks and whether they are consistent with the data blocks metadata available on the disk.

  For example, if the DDB has 1 to 10 unique data blocks that are located on disk location X, the process verifies whether these data blocks are available in that location.

  That is, if the DDB states that the unique data blocks 1 to 10 are valid and available in X volume (for example: x:\CV_MAGNETIC\v_##) and the metadata on the disk states that those data blocks are invalid, then those data blocks are marked as invalid. During subsequent backups, new data is written for those invalid data blocks.

The job also identifies all the files that can be defragmented and logs the details in the DDBMntPathInfo.log in the data mover MediaAgents.

Use this option for a quick verification by checking the presence of the data blocks on the disk so that the new backup jobs refer only to the valid data blocks.

In comparison with the Complete Verification of Existing Jobs on Disk and Deduplication Database and Verification of Deduplication Database options, this option is faster because it does not read the data blocks on the disk. Instead, it ensures that both the DDB and disk are in sync.

Full and Incremental Data Verification Job

Verification of Existing Jobs on Disk and Deduplication Database

The Validate dedup data phase, verifies all the deduplicated jobs (unique data blocks and all references to the blocks) on the disk with the DDB and on the CommServe database.

Data verification process is faster because all the unique blocks are first identified and validated. The unique data blocks that are referred by multiple deduplicated backup jobs are read and verified only once in the verify phase.

Notes:

• The Job Details dialog box displays the Estimated Completion time per phase when you run a DDB verification with Verification of Existing Jobs on Disk and Deduplication Database option.

• The Job Details dialog box displays the Percent Complete per phase when you run a DDB verification with Verification of Existing Jobs on Disk and Deduplication Database option. Both the phases are 50% each.

Use this option for a complete verification of data blocks as well as existing backups on the disk.

This option ensures that existing backup jobs are restorable and can be copied during Auxiliary Copy operations.

Full and Incremental Data Verification Job

Reclaim idle space on Mount Paths

• The Validate dedup data phase of the data verification job runs a quick verification on the deduplication database. For more information, see Quick Verification of the Deduplication Database (listed above in this page).

  The Data Verification jobs for DDB space reclamation is controlled by the Automatically submit Space Reclamation DDB Verification job when free space on Library is below this percent option in Media Management Configuration. For more information on this option, see Media Management Configuration: Service Configuration.

• The Orphan Chunk Listing phase marks those blocks and chunks as orphan that are not referenced by any data block. This phase uses a single stream and if the data verification job is suspended during this phase, then on restarting the job, the listing phase also restarts.

• The Defragment data phase, processes the files that can be defragmented (identified in the first phase) and the orphan chunks (identified in the Orphan Chunk Listing phase) by deleting the invalid or orphan data blocks, thereby reclaiming the unused space.

  Notes:

• The Job Details dialog box displays the Estimated Completion time per phase when you run a DDB verification with Reclaim idle space on Mount Paths option.

• The Job Details dialog box displays the Percent Complete per phase when you run a DDB verification with Reclaim idle space on Mount Paths option. Both the phases are 50% each.

Use this space reclamation option for disk mount paths that do not support sparse files.

Running a data verification job on the ddb with this option enabled defragments the data files that are identified (during the quick verification phase) with the unused space. The valid data blocks are retained. The invalid data blocks that are not being referred to by any backup jobs are deleted thereby reclaiming the unused storage space.

Reclamation Level: Use this slider to select the level of reclamation to be done. On the slider the numbers indicate the percentage of unused data blocks that can be defragmented.

• 1 is equal to 80% (Least aggressive reclamation, low I/O on the disk)

• 2 is equal to 60%

• 3 is equal to 40%

• 4 is equal to 20% (Most aggressive reclamation, higher I/O on the disk)

  For example: By default the slider is set at 3. This indicates that the data files that have 40% or more of invalid data blocks (unused space) and 60% or less of valid data blocks will be selected for defragmentation to reclaim the unused space.

  However, if you set the slider to 4, then the data files that have 20% or more of invalid data blocks (unused space) and 80% or less of valid data blocks will be selected for defragmentation. This will result in a very high I/O on the disk for reclaiming only 20% or more of the unused space.

Full and Incremental Data Verification Job