HP StorageWorks Disk Arrays XP128/XP1024 Owner's Guide (A7906-96012, July 2005)

XP1024 hardware 67
Recovering from a power outage to the disk array
If a power outage to the array occurs, the disk array will maintain its state
and recover when power is restored. The array cache is backed up by
batteries that will maintain its state for a minimum of 48 hours. This length
of time will provide coverage for most outages. In cases where the outage
will extend beyond 48 hours, the batteries can be replaced by an HP CE
which will extend the time, if necessary. You must notify HP support if
your power outage is expected to extend beyond the backup time.