Snapshot of cluster node with RDM disks

Question

I am the DBA and need to have a software install on one of the nodes in a 2 nodes active/active WSFC Win 2012 failover cluster . with SQL on top of the clusters. There is node 1 with SQL cluster 1 running on it as preferred node, and node 2 with SQL cluster 2 running on it as preferred node. Each of the 2 nodes contain C and D drives (vmdk). In addition each node have the cluster drives which are all RDM disks (SQL data drives, log drives, quorum).

All I need to do is get a VM snapshot of node 1 since we need to install a software on its C drive (not RDM). I know that hot snapshot for a VM with RDM disk cannot be done.

However, for steps I consider doing a cold snapshot like below:

1. failover cluster resource from node 1 to node 2, now on node 1 remain just the C drive (OS) and D drive (application) and node 1 do not have any more RDM disks, all RDMs are on node 2.
2. Shutdown node 1 and cold snapshot.
3. Start node 1 and run software install. if software install successful then fail back cluster on node 1 and done change request.
4. if software install unsuccessful then shutdown node 1 , restore cold snapshot back to node 1 then restart and fail back cluster1 back to it.

I realize that only a few of the community might have run into this scenario since this is mostly a VMWare question, wondering if any of you can share a similar scenario.
I contacted our VMWare support resource who told me that in order to get a snapshot, we need to disconnect all RDM from node 1 first, then take snapshot. But since I propose to take cold snapshot as per steps 1-4 then all RDM disks failover to node 2 , and no RDM remain on node 1 where we need to take cold snapshot

I appreciate your help.

Thank you.

Answer 1

Hi,

Thank you for your posting!

Based on your descriptions, I suppose you have two points need dealing with: one is how to take snapshot for a VM in a cluster and the other is your RDM issue. And I think your plan is appropriate for your goal.

In our Microsoft scenario, thing are similar with VMware's. We need to deal with RDM issue as well. However, currently I do not have any similar scenarios as yours at hand except for this one:

https://social.technet.microsoft.com/Forums/it-IT/10d5758d-7529-47ae-ad8c-d251d4419f93/hyperv-2016-move-shared-disk?forum=virtualizzazioneit

Finally, here is my suggestion, I will keep this post on our forum and since the forum is open to all of the public, people who have the similar issue with yours will post under your question and you can check if their scenarios are helpful to deal with yours.

Thank you for your support!

Best regards
Joan

--------------------------------------------------------------------------------------------------------------------

If the Answer is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Thanks for your patience!

So far we haven't found useful scenarios with yours and those that I found were based on Hyper-V service, not sure if your VMware could be applicable to them. So, here is my tips:

1) You can try to follow what you have got from technical supports for VMware first, to see if everything goes fine. I suppose they should be more correlated with your issue.

2) In our place, we will keep track of this issue and conduct professional investigations (which is not within our Q&A scope, but I can help ask our engineers about this issue for you.) You can also go through our Q&A and technet forum to seek for similar scenarios by yourself. Here is the link for our Technet forum:

https://social.technet.microsoft.com/Forums/Lync/en-US/home?category=&forum=&filter=&sort=relevancedesc&brandIgnore=true&searchTerm=Snapshot+of+cluster+node+with+RDM+disks

Thanks for your understanding!

BR,
Joan

---

If the Answer is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.