User Guide

Chapter 6: Technology Background
91
Hot Spare Drive(s)
A hot spare is a disk drive that is connected to the logical drive system but is not
assigned as a member of the logical drive. In the event of the failure of a drive
within a functioning fault tolerant logical drive, the hot spare is activated as a
member of the logical drive to replace a drive that has failed.
The ATI SB600 Controller will replace a failing disk drive in a logical drive with an
unassigned drive, if one is available. The unassigned drive is not part of any
logical drive. Such a drive is called a hot spare drive. There are two types:
• Global – An unassigned disk drive available to any logical drive on the Host
PC.
• Dedicated – An unassigned disk drive that can only be used by a specified
logical drive.
The hot spare policy function lets you select whether a logical drive will access
any unassigned disk drive or a designated drive in the event of disk drive failure.
See “Logical Drive Rebuild” on page 70 and “Create a Spare Drive” on page 80
for information.
The spare drive effectively takes the place of the failed drive and the RAID
system immediately begins to rebuild data onto the drive. When the rebuild is
complete, the logical drive is returned to fault tolerant status.
Maintaining a hot spare drive is a good precaution to protect your logical drive
integrity in the event of drive failure.
Partition and Format the Logical Drive
Like any other type of fixed disk media in your system, a RAID logical drive must
also be partitioned and formatted before use. Use the same method of
partitioning and formatting on an logical drive as you would any other fixed disk.
See “Appendix B: Partition and Format” on page 97.
Migration
Migration is the process of:
• Changing the RAID level of an existing logical drive
• Adding more physical drives to a logical drive while keeping the same RAID
level
See “Logical Drive Migration” on page 67 for instructions how to migrate or
expand a logical drive.
Migration is not available for JBOD.