Usage tips

Follow recommended usage tips to help avoid controller and disk array problems.

The following usage tips will help you maintain your controller.

• Always perform a normal system shutdown before physically replacing or moving the RAID adapter or members of disk arrays. A normal shutdown of the system will flush the adapter's write cache and remove dependencies between the adapter and the physical disks. Using the modprobe -r ipr command will have the same effect as a system shutdown. For systems that support PCI hot plug, PCI hot plug will also have the same effect as a system shutdown.
  Note: A disk that is a failed member of a Degraded disk array can be replaced and the disk array rebuilt while the system continues to run.
• You can physically move disks from one adapter to another. However, if the physical disks are members of a disk array, be sure to move all the disks as a group. Prior to attempting a disk movement, ensure that the disk array is not in a Degraded state because of a disk failure.
• When physically removing disks that are members of a disk array and there is no need to preserve data and no intent to use the disk array again, delete the disk array before removing the disks. This action avoids disk array-related problems the next time these disks are used.
• Always use the "Concurrent device remove" screen to remove and replace a physical disk. For instructions on how to remove and replace a disk, see Removing a failed disk.
• If a disk array is being used as a boot device and the system fails to boot because of a suspected disk array problem, boot into Rescue mode. Linux error logs, the iprconfig utility, and other tools are available to help determine and resolve the problem with the disk array.
• Do not attempt to correct problems by swapping adapters and disks unless you are directed to do so by the service procedures. This is likely to make the problems worse. For additional information regarding problem determination, see Problem determination and recovery.
• Do not confuse the cache directory card, which is a small rectangular card with a round button-shaped battery, for a cache card. The nonvolatile write cache memory is integrated into the main adapter card or integrated into the removable cache card on the newest adapters. The memory itself is not removable, and is battery-backed by the large, rechargeable cache battery pack. The cache directory card contains only a secondary copy of the write cache directory, no cache data, and should never be removed except under very specific cases as described in the MAPs.
• Do not unplug or exchange a cache battery pack without following the procedures as outlined in this section or in the MAPs.
• If multiple errors occur at approximately the same time, look at them as a whole to determine if there might be a common cause.