V11 SP8

Hardware Compression

The hardware compression is only available for data paths that direct data to tape libraries.

When hardware compression is configured:

  • The uncompressed data from the client computer is sent through the data path to the media.
  • The tape drive hardware compressed the data before writing it to the media.

Hardware compression is faster than software compression since it is performed by dedicated circuitry. The hardware compression is suited for direct-connect configurations where the subclient and MediaAgent are hosted by the same physical computer. In such configuration, there are no network bottlenecks that can throttle the transfer of data to the media drives. Therefore, the drives can compress the data as quickly as it is sent by the subclient. In such configurations, hardware compression cannot only boost the virtual capacity of the tape but the performance of the data protection operation as well, because the tape, operating at high speed, stores more data per unit time than it would.

The hardware compression is not applicable for disk libraries and hence the software compression selection for subclient is used for data paths associated with disk libraries.

Hardware compression may be less useful when data secured by data protection operations must compete with other data for network bandwidth. If the network becomes congested, the tape drives can become starved for data. In this condition, the drives still compress the data, but because data is not supplied quickly enough, the drives must stop and restart the media as more data becomes available. As a result, performance might suffer.