When a storage policy with deduplication is configured, signatures are generated for the data blocks during backups, compared and then stored in the deduplication database (DDB).
DDBs are automatically protected by the DDB backup subclient. This subclient backs up all active DDBs managed by the MediaAgent that hosts the DDB.
In the event of DDB failure, you can set up a reconstruction job for an automatic or on-demand restore of the DDB from the DDB backup. You can then reconstruct missing records using storage metadata.