HP MSA 2050 remove disk group and vdrain

[evzar]

Hello!

I have 3 disk groups on my MSA 2050 and going to remove 1 group. I do it by the way that described in manual and VDRAIN process starts. So, all data from removing disk group not going to be deleted, it's just roaming to other disk group. But I do not need these data ! I want to clear, purge it at all! Is it possible, without deleting all pool? Or may be it is possible to delete disk group without VDRAIN?

Thank You.

[Shawn_K]

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

I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.

[kinkingunta]

Dear Shawn,

I don't know about evzar's MSA 2050 setup are

But I also want to ask, since I am also new for MSA 2050, for example the setup are

dg1, 3 SAS with RAID 5 in Pool A

dg2, 3 SAS with RAID 5 in Pool A

dg3. 2 SAS with RAID 1 in Pool A

and dg1, dg2, dg3 were in the same volume (I guess virtual one, named vv01)

and in WIndows 2016 the MSA virtual drive are assign with drive letter

so when we removed dg3, dg pool will initiate a vdrain process, and the data inside dg3 will be moved automatically to remaining dg in pool A that is dg1 and dg2, is that correct?

[evzar]

Hello kinkingunta!

Yes, the pitty problem is in this drain - not needed data will be moved from dg to dg untill you delete whole the pool.

[Shawn_K]

Hello,

In answer to Kinkin's question - if you remove dg3, the data that was written to those drives will be moved automatically to the other disk-groups within the pool. In your example that would be dg1 and dg2.

Since this is virtual system, the volume is striped across the disk-groups within the pool. It is not a one to one relationship with a vdisk owning a volume as you would find with a linear system. With virutal there is no way to associate one virtual volume to a single disk-group. 

In response to Evzar - if you have data that is no longer needed on a volume you can delete that data from the host. That way you will not move unneeded data if you remove a disk-group. The array has no way to determine a single file/database and allow you the ability to delete that file/database from the array. As mentioned before, you can delete the Pool if all the data on volumes associated with that Pool are no longer needed.

Cheers,
Shawn

I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.