Effect of encryption plus compression on NetBackup performance
If a policy is enabled for both encryption and compression, the client first compresses the backup data and then encrypts it. When data is encrypted, it becomes randomized, and is no longer compressible. Therefore, data compression must be performed before any data encryption.
Note the following information about encryption and compression:
If the data provided to NetBackup is already encrypted or compressed, using NetBackup compression or encryption may be counterproductive and consume resources unnecessarily.
If the backup data is stored with MSDP, which performs data compression by default, the client compression should not be enabled. Enabling the client compression may lead to poor deduplication rates in addition to potential poor general performance.