HP B6960-96035 - Manual (Page 121)

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