User`s guide

Document Number: MAN-002000-000 Version 2.6
Sil 4726 Manager User’s Guide
Page 45
8 Configure SAFE Volume Rebuild
Storage Policy
This SiI 4726 feature is provided to manage rebuilds of SAFE volumes.
When is a rebuild necessary?
A rebuild is initiated to restore data redundancy for a SAFE volume that has entered a vulnerable state. In a
vulnerable state, one of the two mirrored disks goes offline or is inaccessible. Although the SAFE volume
remains available during the rebuild process, the volume is susceptible to data loss through damage of the
remaining disk until data redundancy is restored through a rebuild. Host access takes precedence over the
rebuild process. If continuing to use the SAFE volume during the rebuild, the rebuild process will take a longer
time to complete.
Note: The rebuild feature also applies to other SAFE policies such as SAFE and BIG and SAFE and
FAST.
What happens during a rebuild?
The rebuild process restores data redundancy by first utilizing space allocated for a Hot Spare. In case Hot
Spare space does not exist or has already been rebuilt, the SteelVine processor rebuilds to empty space on a
hard disk drive other than the one containing vulnerable data. Following a rebuild, it is not necessary to
designate space to a Hot Spare for a subsequent rebuild to occur.