NetRAID - RAID Tutorial

14
logical drives (RAID levels 1, 3, 5, 10, 30, or 50.) Data in RAID 0 logical
drives cannot be rebuilt, and must be restored from a backup copy.
More About Rebuilding Data
A configuration of RAID 1, 3, 5, 10, 30, or 50 has built-in redundancy. If a drive
in one of these RAID levels fails, the RAID subsystem continues to operate, but
no additional redundancy is provided and the logical drive becomes "degraded."
Another drive failure will cause data loss.
A disk that is being rebuilt is in the process of having data restored from one or
more degraded logical drives. The rebuild operation is different for different
RAID levels. To rebuild a RAID 1 drive, the system merely copies the mirrored
disk. A RAID 3 or 5 rebuild is a complex operation involving multiple read and
write operations to reconstruct data from parity.
A rebuild operation is considered to be a background operation. Data on the
degraded logical drive continues to be available even during the rebuild.