Hello,
If the disk-group has data in it, then the VDRAIN process will automatically occur. There is no option to enable or disable VDRAIN. VDRAIN moves the data becuase the volume associated with the disk-groups has the data spread across all the disk-groups for that volume. If you deleted a disk-group without moving the data to the other disk-groups you would cause data integrity problems.
As long as you do not need any of the data within any of the disk-groups associated with the Pool, then you can delete the Pool. Deleting the Pool would be quicker than a VDRAIN process. However, deleting a Pool is a permenant action that cannot be undone and once done you will not be able to recover any of the data previously contained within that Pool. You will need to verify that the data currently contained within the Pool is no longer needed or you have a completed and verified backup of all data before you delete a Pool.
If more information is needed please refer to the MSA 2050 SMU Guide: https://support.hpe.com/hpsc/doc/public/display?docId=a00017707en_us
I suggest starting on page 22 which has good information on Pools.
Cheers,
Shawn
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