Shutting Down A Controller Module - Lenovo ThinkSystem DS Series Hardware Installation And Maintenance Manual

2. Run the show disk-group-statistics command a second time.
This provides you a specific window of time (the interval between requesting the statistics) to determine if data
is being written to or read from the disk group. Record the numbers displayed.
3. To determine if any reads or writes occur during interval, subtract the set of numbers you recorded in
from the numbers you recorded in
If the resulting difference is zero, then I/O has stopped.

If the resulting difference is not zero, a host is still reading from or writing to this disk group.

Continue to stop I/O from hosts, and repeat
NOTE: See the CLI Reference Guide for additional information. Optionally, you can use the SMC to monitor IOPs
and MB/s.

Shutting down a controller module

Shutting down the Storage Controller in a controller module ensures that a proper failover sequence is used, which
includes stopping all I/O operations and writing any data in write cache to disk. If the Storage Controller in both
controller modules is shut down, hosts cannot access the system's data. Perform a shut down before you remove a
controller module from an enclosure, or before you power off its enclosure for maintenance, repair, or a move.
Use the SMC or the CLI to perform a shut down.
Using the SMC
1. Sign-in to the SMC
2. In the System panel in the banner, select Restart System.
The Controller Restart and Shut Down panel opens.
3. Select the Shut Down operation, which automatically selects the controller type Storage.
4. Select the controller module to shut down: A, B, or both.
5. Select OK. A confirmation panel appears.
6. Select Yes to continue; otherwise, select No. If you selected Yes, a message describes shutdown activity.
NOTE: If an iSCSI port is connected to a Microsoft Windows host, the following event is recorded in the
Windows event log: Initiator failed to connect to the target.
NOTE: See the Storage Manager Guide for additional information.
Using the CLI
1. Log-in to the CLI.
2. In your dual-controller system, verify that the partner controller is online by running the command;
show controllers
3. Shut down the failed controller—A or B—by running the command:
shutdown a or shutdown b
The blue OK to Remove LED (back of enclosure) illuminates to indicate that the controller module can be
safely removed.
4. Illuminate the white Identify LED of the enclosure that contains the controller module to remove by running
the command:
set led enclosure 0 on
step 2.
step 1 and step 2 until the difference in step 3
step 1
is zero.
Replacing an IOM 129