VMware Rdms and microsoft SQL clustering - Svmotion & Migration plan

[pjaryan]

Hello Friends,

I need your help in preparing the Implementation plan where we have the plan to migrate 2 virtual machines which are part of Microsoft cluster and have some RDM's configured.

Here we have 2  requirements i.e.

1) SVmotion from EMC to HP3PAR storage.

2) Migration of Virtual machines from 1 esx clsuetr to some new VMware cluster.

[daphnissov]

Need more information. What version of vSphere at the source and destination? Are these pRDMs? What is the storage connectivity in use?

[vijayrana968]

daphnissov​

So the requirement is to move 2 VMs (Microsoft fail-over Clustered VMs) having 6 pRDMs .. from one cluster to another hosts cluster without downtime. Quorum and data disks are clustered as pRDMs, the goal is to use new 3PAR storage moving from old EMC. Both, EMC and 3PAR storage is accessible from both clusters.

vSphere 6, source and destination.

[daphnissov]

What is the EMC storage in use at the source, and how are both arrays connected to both sets of hosts?

[daphnissov]

Well, nevermind as it's largely inconsequential to this topic. The short answer is: this isn't possible. If you have pRDMs, while you can move the VMs themselves and even the RDM pointers, the extents cannot be migrated. If you wish to convert that to a VMDK and update your sharing mechanism, then that would be possible. Another technique I've seen used to migrate away from pRDMs is to use guest-based disk mirroring, but all of these options will require some downtime and it can't be helped. You may take this opportunity to update these systems to avoid using pRDMs as you've now seen the consequence of that type of lock-in.

[pjaryan]

If we get the downtime, what will be the action plan.

[daphnissov]

That depends on what direction you want to go. Unless there is some unusual tool which allows you to replicate full LUNs from EMC over to 3PAR, if you decide to stick with using pRDMs you will be forced to manually recreate them somehow. See the setup guide (PDF) on vSphere 6.5 for more information.

[vijayrana968]

Thanks for your input. That's make sense moving extent to new array isn't possible, We'll have to check for LUN replication with storage team.

As you said for mirroring option in guest OS but I am not sure how's that gonna work as these RDMs are attached as MS clustered shared disk inside guest OS on both nodes, these will be online on one node at given time.

One article I have found is Re: How to Migrate and Convert Physical RDMs

I’m not sure if these steps in above article  gonna do what exactly we want or not, we need to dig up with this as we haven't perform this kind of activity before.