IBM N series Hardware Manual page 156

Note: It might take up to a minute for the system to complete discovery.
The configuration is listed in the System Storage configuration field. It should be the fourth
line of output.
Caution: If your system configuration is shown as something other than Multi-Path HA,
you cannot continue with this procedure.
2. If you are replacing SAS copper cables with SAS optical cables, verify that the disk
shelves in the storage system have the latest version of disk shelf firmware by completing
the following steps; otherwise, go to Step 4:
a. Enter the following command at the storage system console:
sasadmin expander_map
b. Locate the disk shelf firmware information for the disk shelves in the output.
Example: 0151 is the disk shelf firmware version for shelf number one (Slot A/IOM A) in
the storage system:
Expanders on channel 4a:
Level 3: WWN 500a0980000840ff, ID 1, Serial Number ' SHU0954292G114C',
Product 'DS424IOM6', Rev '0151', Slot A
c. Compare the firmware information in the command output with the disk shelf firmware
information at the N series support site to determine the most current disk shelf
firmware version.
3. The next step depends on how current the disk shelf firmware is:
If the firmware version in the command output is the same as or later than the most
current version on the N series Support Site, no disk shelf firmware update is needed.
If the firmware version in the command output is an earlier version than the most current
version on the N series Support Site, you must update the disk shelf firmware.
You can run the commands from either controller.
4. Replace SAS cables by completing the following steps. You can ignore cabling messages
that might appear on the console:
Note: When you are replacing an SAS cable, wait a minimum of 10 seconds before you
plug in the new cable so that the system can detect the cable change.
a. Replace cables on Side A one cable at a time.
The Side A cables are the cables that are connected to IOM A of each disk shelf.
b. Verify that you correctly replaced the SAS cables by entering the following command at
the system console:
sysconfig
For HA pairs operation in 7-Mode, you can run the command from either controller. For
clustered systems, you must run this command from the nodeshell of the target
controller.
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IBM System Storage N series Hardware Guide
Note: It might take up to a minute for the system to complete discovery.