Toshiba Magnia 560S - Manual (Page 35)

RAID Overview
Introduction to RAID
17
Disk Rebuild
You rebuild a disk drive by recreating the data that had been stored on the drive before
the drive failed. Rebuilding can be done only in arrays with data redundancy such as
RAID level 1, 5, 10, and 50.
Standby (warm spare) rebuild is employed in a mirrored (RAID 1) system. If a disk
drive fails, an identical drive is immediately available. The primary data source disk
drive is the original disk drive.
A hot spare can be used to rebuild disk drives in RAID 1, 5, 10, or 50 systems. If a hot
spare is not available, the failed disk drive must be replaced with a new disk drive so
that the data on the failed drive can be rebuilt.
The RAID Controller Kit-G controller automatically and transparently rebuilds failed
drives with user-definable rebuild rates. If a hot spare is available, the rebuild starts
automatically when a drive fails. RAID Controller Kit-G automatically restarts the
system and the rebuild if the system goes down during a rebuild.
Rebuild Rate
The rebuild rate is the fraction of the compute cycles dedicated to rebuilding failed
drives. A rebuild rate of 100 percent means the system is totally dedicated to rebuilding
the failed drive.
The RAID Controller Kit-G rebuild rate can be configured between 0% and 100%. At
0%, the rebuild is only done if the system is not doing anything else. At 100%, the
rebuild has a higher priority than any other system activity.