- IBM switch Users and Maintenance Guide

Replacing a RAID controller
When instructed to do so by the DS4000 Storage Manager client, replace a RAID
controller that has failed.
The procedure for replacing a failed controller is different for DS4100
single-controller and base (dual-controller) storage servers. If a controller in a
DS4100 base storage server fails, you can replace the failed controller without
interrupting data processing. The system will automatically update the firmware for
the new controller to match the configuration database.
If the controller in a DS4100 single-controller storage server fails, you may need to
manually update the firmware level to match the configuration database. If the
firmware level of the new controller matches the configuration database, the storage
server will boot normally after you install the new controller. If the firmware level
does not match the database, the storage server will reach a stop state in the boot
process, and you will need to manually update the firmware level to match the
configuration database.
Attention: Because the replacement RAID controller has a different WWNN that
the original RAID controller, you must perform the following tasks in order to bring
the DS4100 single-controller storage server to running (optimal) state after you
replace the RAID controller.
v Reboot the host server that has mapped logical drives from the DS4100
single-controller storage server.
Rebooting the host server enables the multipath failover to recognize the logical
drives under the new WWNN. In addition, if your multipath driver uses the
WWNN of the controller as part of the LUN identification, you may have to
reconfigure the LUN failover/failback path information.
v Use DS4000 Storage Manager to rediscover the new RAID controller.
To rediscover the new RAID controller, remove the existing DS4100
single-controller storage server entry in the management domain of the DS4000
Storage Manager client Enterprise Management Window (EMW), and then add
the DS4100 single-controller storage server back into the management domain
using the in-band or out-of-band management method. See step 6 on page 104.
v Re-enable the premium feature keys.
After you replace the RAID controller in a DS4100 single-controller storage
server, all of the enabled premium feature keys are displayed as being
out-of-compliance. Use the existing key files to re-enable the premium feature
keys.
v If you create zones using the RAID controller WWNN, update your zoning
definitions with the new WWNN for the replacement RAID controller.
Important
The replacement RAID controller CRU does not come with a RAID controller
cache battery installed, nor does it come with the mounting hardware that
holds the battery in place inside the RAID controller. You must remove the
cache battery that is inside the existing RAID controller that you are replacing,
and install that battery inside the replacement RAID controller CRU, using the
battery unit mounting hardware taken from the existing controller. The steps to
remove and replace the battery are included in the following procedure.
96 IBM TotalStorage DS4100 Storage Server: Installation, User’s, and Maintenance Guide