The present invention provides a method for reducing rebuild time on a
Redundant Array of Independent Disks (RAID) device. A first stripe of the
RAID device is selected. Write-back caching on a drive being built is
enabled. Data and/or parity may be read from at least one other drive.
The at least one other drive and the drive being built belong to a same
stripe of the RAID device. When a RAID level of the RAID device is 5, the
at least one of data or parity is XORed (exclusive ORed) to obtain a
result. When the RAID level of the RAID device is 1, the at least one of
data or parity is data and treated as the result. The result is written
to a second drive, which is a repaired, replaced, or hot-spare drive for
the drive being built.