Best practice on changing Raid Type on Raid Group

Hi,

I've moved this thread to the CLARiiON Forum. The forum called Forum Suggestions/Features is to discuss the features and functionality of the Support Forums.

Thanks,
Erich

PJ,
If the end goal is to have existing data protected differently, you can use the LUN Migration feature to move data in an online manner without requiring host downtime.
When using LUN Migration, an equivalent amount of free space needs to be available on the new RAID Group.
For example - if a 100GB LUN exists on a RAID Group configured as RAID 5, the data can be moved to a 100GB LUN that exists on a different RAID Group configured as RAID 10.
At the completion of that move, the original 100GB of RAID 5 becomes free space available for re-use.
All host-facing attributes of the LUN remain unmodified, even though the LUN now exists on a different RAID Group with (in this example) a different level of RAID protection.

If the end goal is to fundamentally change how a set of disks are bound, that can be done if/when all the LUNs that exist on the RAID Group have been migrated - there is not a feature that will modify the underlying RAID level of a set of disks while the RAID Group contains LUNs with "live" data.

Regards,
DGM

Please just make sure to check your FLARE version. If you are running anything older than R16 then I recommend you get on R19 (at least) to perform your LUN migration.

Regards,
Shmac

Hi All

Kind of related - so posted here since I can't seem to figure out where to post

Got a 3 node AAP exchange cluster but more a windows question. LUNs need to be expanded. Now EMCs upport says the migration can happen with the cluster up.

The only part I was worried about was increasing the partition size on the host with diskpart once the migration had completed. The question is - can I do that with the cluster live? And are there any special procedures I need to do. I've been thru the emc exchange best practices stuff but it doesn't mention clustering. I've got a powerlink login so links are fine

Microsoft has a KB article to perform the lun expansion. I believe the KB article takes the cluster offline, but I have seen customers do this online.

diskpart>select the disk to extend and
extendvg

Works like a champ, but Microsoft will have the final word to what they support and do not support. Look up the KB article for details. Pretty easy to find.

Paul M.

i believe Microsoft does not officially support diskpart, but we use it all the time whenever we expand our metaluns and need to expand NTFS partition. We do it on win2k and win2k3 clusters online without any issues.

Correct me if I am wrong, but I believe if you take a clustered disk offline, you do not have access to it and therefore cannot expand it with diskpart.

We always expand our LUNS and run diskpart on all of our clusters. We also test fail over between cluster nodes to ensure the other node accepts the new size.

Periodically we'll see the other node does not, and at the console of the 2nd cluster node we'll have a message asking us to accept a generic volume. Once we ok that, the newly expanded lun easily tranfers between nodes.

On another note, we've run diskpart only to have the process fail. It will appear in Disk manager as expanded, but within explorer it has not. Microsoft offers a fix for this called FSExtend that resolves that issue.

Hope this helps.

cableguy,

If you are runninng Win2k, go here:

http://support.microsoft.com/default.aspx?scid=kb;en-us;325590

Download the back port of diskpart and install onto servers.

If you are running Win2k3 then you are good to go.

I can tell you for a fact that we have done over a hundred partition expansions on Live MS Win2k3 single server and multi-node clusters without any issues. I can not speak for Win2k but 2k3 works is range rover all wood.

Regards,
Shmac