User's Manual

Controllers 73
The following describes some of the RAID controller features and provides
links to a more detailed explanation. For information on which controllers
support which features, see
Supported Features .
• Hot spares —On RAID controllers, a hot spare is a backup for a disk that
fails. See the Protecting Your Virtual Disk with a Hot Spare.
•
Rebuilding data. You can rebuild data from a failed physical disk if the
disk is a member of a redundant virtual disk. See Rebuilding Redundant
Information.
•
Virtual disk expansion —Virtual disk expansion enables you to expand the
capacity of a virtual disk while it remains online by adding additional disks
to the virtual disk. This feature is also known as online capacity expansion
(OLCE). See Virtual Disk Tasks.
•
RAID migration —After creating a virtual disk, you can change the RAID
level. See Reconfiguring/Migrating Virtual Disks.
•
Moving physical and virtual disks to another controller —This freature
enables you to move physical and virtual disks from one controller to
another. See Moving Physical and Virtual Disks from One System to
Another.
•
Read, write, and cache policies —The manner in which a controller reads
and writes data can vary. The read, write, and cache policies have
implications for data encryption and system performance. See RAID
Controller Read, Write, Cache, and Disk Cache Policy.
•
Check consistency —A check consistency determines the integrity of a
virtual disk’s redundant data. When necessary, this feature rebuilds the
redundant information. See Maintain Integrity of Redundant Virtual
Disks.
•
Patrol Read —Patrol Read identifies disk errors in order to avoid disk
failures and data loss or corruption. For more information, see Set Patrol
Read Mode.
•
Disk migration or foreign configurations —Some controllers enable you
to move physical disks that contain one or more virtual disks to another
controller. The receiving controller is able to recognize and import the
foreign configuration (virtual disks). For more information, see Foreign
Configuration Operations.