Server Administrator Storage Management 8.2 User’s Guide

Different controllers have different features. If you have more than one controller attached to your system, you may notice that the tasks displayed on the Information/Configuration page of the controller are different for each controller.

Controllers may also have differences in their read, write, and cache policies as well as how they handle hot spares. You should be aware of these differences when creating virtual disks and assigning hot spares.

The following describes some of the RAID controller features and provides links to a more detailed explanation. For information on the features supported by the controllers, see Supported Features.

• Hot spares — On RAID controllers, a hot spare is a backup for a disk that fails. See 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 Or Migrating Virtual Disks .
• Moving physical and virtual disks to another controller — This feature enables you to move the physical and virtual disks from one system 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 the redundant data on a virtual disk. When necessary, this feature rebuilds the redundant information. See Maintaining The Integrity Of Redundant Virtual Disks .
• Patrol Read — Patrol read identifies disk errors to avoid disk failures, data loss, or corruption. For more information, see Setting The 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 .