HP B6960-96035 manual Object mirroring, Backup performance

Figure 35 Object mirroring

Selection of devices

Object mirroring is load balanced by default. Data Protector makes optimum use of the available devices by utilizing as many devices as possible. Devices are selected according to the following criteria in the order of priority:

•devices of the same block size are selected, if available

•locally attached devices are selected before network attached devices

When you perform an object mirror operation from the command line, load balancing is not available.

Backup performance

Object mirroring has an impact on backup performance. On the Cell Manager and Media Agent clients, the impact of writing mirrors is the same as if additional objects were backed up. On these systems, the backup performance will decrease depending on the number of mirrors.

On the Disk Agent clients, there is no impact caused by mirroring, as backup objects are read only once.

Concepts guide 121