See SMU Reference Gudie Page 44:
1. Perform one of the following:
In the banner, click the system panel and select Restart System.
In the System topic, select Action > Restart System.
2. Select the Shut Down operation, which automatically selects the Storage controller type.
3. Select the controller module to shut down:Controller A, Controller B, or both.
4. Click OK. A confirmation panel appears.
5. Click Yes to continue. Otherwise, click No. If you clicked Yes, a message describes shutdown activity.