You can delete all but one partition of a RAID 1 (mirror) and only one partition at a time for a RAID 5. To delete a RAID 1 partition, you must delete its RAID.
In iManager, click Storage > Software RAIDs.
For instructions, see Section 10.1.5, Accessing Roles and Tasks in iManager.
Select a server to manage.
For instructions, see Section 10.1.6, Selecting a Server to Manage.
Make sure that there is no I/O for the volumes on the RAID device by deactivating the volume.
Click Volumes.
Select the volumes in the RAID device pool.
Click Dismount.
In the Software RAIDs list, select a device.
Wait for the page to refresh before continuing.
Click the Partitions View Details icon.
This opens the Partition page. It displays a list of all the partitions that currently exist on the selected device.
Select a partition from the Partitions list, click Delete, then click OK.