Migrating Hyper-V Cluster from "2008 R2" to "2012 R2" with cloned CSV

I'm working on migrating a 3x host "2008 R2" Hyper-V Cluster to a 2x host "2012 R2" Cluster. We'll not be re-using the current hosts, we have 2 new servers.

Current cluster is connected to a Compellent FC SAN, 1x CSV volume and 1x Quorum drive mapped (presented) to all 3x hosts.

One of the VM has a large pass-through disk (E:\) and it is clustered as well. Live-Migration between hosts works with all VMs including VM with this pass-through disk.

The new 2012 hosts are also connected to the same SAN but nothing is presented to them yet. They don't have the cluster roles installed yet.

I came across below blog post. The idea of cloning (replay) the CSV volume in SAN and using that during the migration instead of touching the current cluster config seems safer way to go. I'd like to be able to go back to the old cluster if something goes wrong or migration fails.


I'd like to know if anyone has done it this way, any recommendations or suggestions about that. I can't find any other step-by step instructions about this method anywhere.

I'm also concerned about the VM with pass-through disk, it's 1.2TB in size. I'm hoping that after I migrate all the VMs, I'll move this volume to the new hosts, add it to the cluster, and attach it to the same VM. Has anyone done it and would like to share how they did it?

Thank you in advance..
Sahap YuzerAsked:
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MaheshConnect With a Mentor ArchitectCommented:
You can't remove quorum unless you take complete source cluster down

Note that you need to prepare target cluster with new quorum in advance prior to start the migration
Hence only CSV volume (LUN) need to be mapped to target cluster and it will remain offline until you remove it from source cluster
Once you removed that LUN (CSV) from source cluster after migrating all VMs, you need to activate it on target cluster

Ryan McCauleyData and Analytics ManagerCommented:
I wish I could say I'd done this and used the plan you've attached, but I haven't - however, the process makes sense and the steps supplied in the attached plan look like they cover all the bases. Ensure you've got good backups in place, but in your situation, that's the plan I'd proceed with.

As for the pass-through disk, you've got the steps right - remove it from the cluster, mount it to the new servers, add it to cluster control, and then attach it to the same VM. The only potential improvement I could see here is if your SAN supports snapshots - before you unmounts, migrate, and remount this giant LUN, a snapshot would allow you to fail back to the previous state in case mounting it to the new cluster has unexpected impact. I can't see how it possibly could, but just one more thought to protect yourself against damaging the LUN in case there's an issue (or in case any config is somehow upgraded on it when you mount it to 2012, you can still move it back to the old cluster and remount it there).

It sounds like you're on the right track - I wish I could provide more than support for the plan, but without the ability to test it firsthand on a lab system (which it sounds like you don't have), I think that's as close as you're going to get before you actually migrate it :)
MaheshConnect With a Mentor ArchitectCommented:
You can do that:
Note: Live Migration of virtual machines (VMs) from Windows Server 2008 R2 to Windows Server 2012 is not supported.  
As a result, migrating VMs to Windows Server 2012 can be fast, but it is not a zero-downtime event - a brief maintenance window is required to cut over to the new cluster roles.  
Fortunately, cluster migration can be tested with no impact to a running cluster, so that issues can be identified prior to actual migration.

Since this is cluster migration you need to map old cluster storage to new cluster in advance and storage remains mapped with both clusters, only it should be offline on new cluster

I'd create one small CSV volume on source cluster 1st, create new highly available VM and then migrate that VM with cluster migration wizard and get familiarity and confidence 1st and to identify any issues prior to proceed with all VMs migration
Because If one VM on a CSV disk is selected for migration, the Cluster Migration Wizard will require all VMs (and auto-select them for you) on that CSV to be migrated too.

Also I'd pre create all required VM networks in advance on target cluster

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Also check below blog for possible downtime required

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Sahap YuzerAuthor Commented:
Thank you for your replies, I think it's a good idea to test it on a smaller CSV, thanks. I'm surprised that not many people had done it this way. I hear a lot of the 2008 clusters were using SANs that were connected to hosts via FC or iSCSI.

One other thing I can use some ideas is that one of the VM has a NIC for DMZ. It's connected to one of the host's NIC, configured as hyper-v switch, and mapped to this VM. This VM is not "clustered". I'm guessing the migration wizard will only detect the VMs on the CSV right? How would you go about moving this VM to one of the new hosts? The new host serve has one extra NIC and connected to DMZ for this.

Thanks in advance.
In reality those who don't have cluster also do not have a CSV volumes and what they do actually have a SAN attached to server.
In that case above method is not suitable \ Possible
Those people prefer export - import method for migrating VM from 2008 \ 2008 R2 to 2012 \ 2012 R2 as this is one of the simplest method and only one VM is affected at a time as you have to shutdown VM 1st in order to export
The other approach is if you have SCVMM 2012 SP1, then you can add your source and target hyper-v server to SCVMM 2012 SP1 and from there you will just use P2V method to migrate old server VMs on the fly to target Hyper-V server
(Note that here virtual machines are considered as physical machines as V2V is not possible within Hyper-V versions and its possible in Hyper-V and VMware)

When you migrate VM from cluster to another cluster, it is offline on target, here you will get chance to check all VM settings and here you probably attach DMZ network to VM in advance
In reality within VM migration wizard you get a chance to set target VM network and then you will migrate

Sahap YuzerAuthor Commented:
Thanks, I think using SCVMM or just export/import the stand-alone VMs will be the way to go in this case. I'll move them first and then the cluster.

When migrating the cluster, do we move only the CSV or we also move the Quorum volume? In another words, do we need to take a snpshot of only the CSV or we need to make a copy of both and then move both CSV and Quotum volumes to the new cluster?

Thank you.
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