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Media Management Configuration: Deduplication

Use the following parameters to establish Deduplication parameters.

Parameter

Description

Config param to convert reconstruction to full automatically on invalid DDB backup job

Definition: Specifies that the DDB reconstruction job is transformed to a full reconstruction job when the last DDB backup job is invalid.

Default Value: 0

Range: 0 (disabled) or 1 (enabled)

Config param to mark jobs verification failed for read errors

Definition: Specifies that, during restore auxiliary copy, or synthetic full operations, if a data chunk is found that has read errors, then the Data Verification Status of the job is marked as Failed.

Default Value: 1

Range: 0 (disabled) or 1 (enabled)

Days to keep DDB on source location after successful move partition job

Definition: Specifies the number of days to keep DDB files on the source MediaAgent after a successful move partition job.

Default Value: 0 day

Range: 0 to 30 days

DDB horizontal scaling threshold free space percentage

Definition: Specifies the percentage of free space that must be available on a deduplication database partition disk to create a new deduplication database.

Default Value: 0

Range: 0 to 50

DDB horizontal scaling threshold number of subclients per DDB

 

 

Definition: Specifies the threshold for the number of subclients that are associated with a deduplication database after which the software creates a new deduplication database for the storage policy copy. Configure a value other than zero (0) for the parameter to take effect.

Default Value: 0

DDB Reconstruction prune replay batch count

Definition: Specifies the number of prunable data blocks that can be sent in a batch to a deduplication database.

Default Value: 1000

Range: 1 to 100,000

DDB Reconstruction prune replay retry count

Definition: Specifies the number of times that DDB Reconstruction has to replay the pruned data blocks before reporting failure.

Default Value: 100,000

Range: 1 to 100,000

Deduplication pruning batch size

Definition: Specifies the number of job records that can be sent in a batch for deduplication pruning from the CommServe to the MediaAgent.

Default Value: 1000

Range: 0 to 10,0000

Enable horizontal scaling of DDBs

Definition: When you enable horizontal scaling, the software regularly monitors the deduplication databases (DDBs) that exist before and after enabling the horizontal scaling. The software marks a DDB as full upon reaching the system threshold limits, and then stops association of any new subclients to the DDB. However, the existing subclients still back up to the current DDB.

When you create a storage policy or a storage policy copy, the software creates new DDBs for three different data types - virtual machines, databases, and file system agents. Any new subclients are associated to a DDB based on their data type.

when a DDB of a data type is marked full upon reaching the system threshold limits, the software automatically creates a new DDB for the data type, and associates any new subclients of the data type to the new DDB.

Default Value: 1

Range: 0 (disabled) or 1 (enabled)

Usage: With the creation of separate deduplication databases for three different data types—virtual machines, databases, and file system agents—when you create a storage policy copy, you can achieve maximum deduplication efficiency. Horizontal scaling improves deduplication efficiency because similar data types deduplicate more efficiently than dissimilar data types.

When you create a storage policy copy, if one of the following conditions is true, then horizontal scaling does not apply for the copy and the Commvault software does not create the three deduplication databases:

  • You select a library that is associated with a MediaAgent that is on Service Pack 14 or an earlier version.
  • The deduplication database or a deduplication database partition is hosted on a MediaAgent that is on Service Pack 14 or an earlier version.

When you enable the horizontal scaling of deduplication databases, the auxiliary copy operation uses the Use Scalable Resource Allocation option by default, and you cannot turn off the option. For more information, see Performing an Auxiliary Copy Operation.

When you enable horizontal scaling of deduplication databases, you can update values for the DDB horizontal scaling threshold free space percentage and DDB horizontal scaling threshold number of subclients per DDB parameters in the current Deduplication tab.

Note:

  • Any new subclients from the client computers with Service Pack 14 and more recent service packs associate to the new deduplication databases created with horizontal scaling for backups.
  • The existing subclients from the client computers with Service Pack 14 and more recent service packs continue to use the earlier deduplication database for backups.
  • The existing and any new subclients from the client computers with Service Pack 13 and earlier service packs continue to use the earlier deduplication database for backups.
  • You can use the Move Clients to New DDB workflow to move the subclients of a client computer from the previous full deduplication database (DDB) to a new DDB created for their data type. For instructions, see Moving Clients from a Full DDB.

Enable Index Free Restores for DDB Reconstruction

Definition: Specifies that the regular DDB reconstruction job will use an index free restore.

Default Value: 0

Range: 0 (disabled) or 1 (enabled)

Usage: If you encounter problems with the DDB reconstruction that uses an index based restore by default, set the value for this parameter to 1 to perform DDB reconstruction job using an index free restore. After performing the DDB reconstruction, turn off this parameter by setting the value to 0 again.

Option to retain extra DDB backups for every partition

Definition: Specifies the number of DDB backups that can be retained for each partition.

Default Value: 1

Range: 1 to 4

Usage: If multiple DDB backups for each partition are retained and the most recent DDB backup is corrupted, then you can use one of the retained DDB backups for DDB reconstruction.

Last modified: 4/21/2020 5:57:29 PM