Administrator Guide

Removing disk groups
You can delete a single disk group or select multiple disk groups and delete them in a single operation. By removing disk groups,
you can also remove pools. Removing all disk groups within a pool will also trigger the automatic removal of the associated pool.
If all disk groups for a pool have volumes assigned and are selected for removal, a confirmation panel will warn the user that the
pool and all its volumes will be removed. For linear disk groups, this is always the case since linear pools can only have one disk
group per pool.
Unless a virtual pool consists exclusively of SSDs, if a virtual pool has more than one disk group and at least one volume that
contains data, the system attempts to drain the disk group to be deleted by moving the volume data that it contains to other
disk groups in the pool. When removing one or more, but not all, disk groups from a virtual pool, the following possible results
can occur:
● If the other disk groups do not have room for the data of the selected disk group, the delete operation will fail immediately
and a message will be displayed.
● If there is room to drain the volume data to other disk groups, a message will appear that draining has commenced and an
event will be generated upon completion (progress will also be shown in the Current Job column of the Related Disk Groups
table).
○ When the disk group draining completes, an event will be generated, the disk group disappears, and the drives for it
becomes available.
○ If a host writes during the disk group draining, which results in there not being enough room to finish the draining, an
event will be generated, the draining terminates, and the disk group will remain in the pool.
NOTE: Disk group removal (draining) can take a very long time depending on a number of factors in the system, including
but not limited to: large pool configuration; the amount of I/O traffic to the system (e.g., active I/O pages to the draining
disk group); the type of the disk group page migration (enterprise SAS, midline SAS, SSD); the size of the draining disk
group(s) in the system; and the number of disk groups draining at the same time.
If you remove the last disk group in a virtual pool, the system will prompt you to confirm removing the pool, too. If you choose
yes, the pool will be removed. If you choose no, the disk group and the pool will remain.
NOTE:
If the disk group is the last disk group for a pool that is used in a peer connection or it contains a volume that is
used in a replication set, the Remove Disk Groups menu option will be unavailable.
Remove a disk group
1. In the Pools topic, select the pool for the disk groups that you are deleting in the pools table. Then, select the disk groups in
the Related Disk Groups table.
NOTE:
To see more information about a pool, hover the cursor over the pool in the table. Viewing pools contains more
details about the Pool Information panel that appears.
2. Select Action > Remove Disk Groups. The Remove Disk Groups panel opens.
3. Click OK.
4. Click Yes to continue. Otherwise, click No. If you clicked Yes, the disk groups and their volumes are deleted, the pool for the
disk groups might be deleted, the disks for the disk groups become available, and the Related Disk Groups table is updated.
Expanding a disk group
You can expand the capacity of a linear disk group, or a virtual disk group with a RAID level set to ADAPT up to the maximum
number of disks that the storage system supports. Host I/O to the disk group can continue while the expansion proceeds. You
can then create or expand a volume to use the new free space that becomes available when the expansion is complete. As
described in About RAID levels, the RAID level determines whether the disk group can be expanded and the maximum number of
disks the disk group can have. This task cannot be performed on an NRAID or RAID-1 disk group.
The following table summarizes disk group types that can be expanded.
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Working in the Pools topic