When using the Data Domain Boost Access library, we recommend to use Commvault deduplication and compression with backups. Keep all of the Commvault data being written in the same format to maximize the space savings provided by the device level deduplication of the Data Domain.
Do not enable encryption on backups in Commvault. This prevents the Data Domain from further deduplicating the data written on the device side. If you need to use encryption of the data at rest, enable this feature on the Data Domain.
To encrypt data between the Commvault servers and the Data Domain devices, enable the Encryption of data in flight through DD Boost option in the Data Domain console. For the best performance with Encryption of data in flight through DD Boost option, select anonymous authentication mode.
Deduplication Database Settings
Set the value of the Do not Deduplicate against objects older than n day(s) option to 90 days. For more information, see Deduplication Database Properties - Settings.
If you want to have multiple copies of data across two or more Data Domain devices, consider using the MTree Replication feature of Data Domain, because this is more efficient than performing auxiliary or DASH copies.
For other best practices, refer to Best Practices for Disk Libraries.