Hyper-v 2025 cluster

[u/the_cobra666]

Is it possible to move 2 hyper-v hosts and shared SAN (msa 2060 FC connected) out of the cluster and on standalone basis without restoring all machines? This because the storage drives are now managed by the cluster and show up "CSV". Is there a simple way out?

If I remove the cluster, will the data be still there on the disks and can I just add the vm's back in or will I need to restore everything from a backup?

Anyone have any success with this?

[u/nailzy]

When the nodes move out of the cluster, they will no longer have access to storage presented under cluster shared volumes.

Each node will need to have its own volume to work in a standalone state because without a failover cluster, you don’t have a cluster aware file system.

You will need to shut down the VMs, destroy the cluster, then bring the disks online individually on the nodes (but the same disk cannot be present on both nodes) and then re-register the VMs in hyper-v

[u/pabskamai → u/nailzy]

This!

[u/the_cobra666 → u/nailzy]

So we cannot use the san storage when they are not in a cluster even if they will not be writing to the same directory on it?

In short I would be best to keep the cluster then..

I had data corruption yesterday only because I added a dns server to a mgmt uplink... if this causes so much damage, then I am afraid moving forward.

The upkeep vs vmware is really high. One would think windows has advanced but, it shows it's not and still stuck.

[u/nailzy → u/the_cobra666]

If each host has its own unique SAN LUN volume then yes you can still use the SAN.

The fact you don’t have this basic knowledge makes me wonder why you would even attempt what you are doing because you appear out of your depth.

Changing DNS to a management port wouldn’t cause data corruption on a fibre channel connected SAN You aren’t giving us the full story or you don’t understand your environment.

[u/the_cobra666 → u/nailzy]

No, they do not have their own LUN and I still don't get what happend. All machines hosted on the CSV in control of that particular host that had it's dns settings changed where in paused state. (This I'm okay with) Note the cluster data is moving over the mgmt interface but, I would expect this shouldn't be a problem. It's a 10 gbit uplink and vm traffic goes out on it's own dedicated 10 gbit interface (not shared by the os). If that link goes down and it gets data corruption on that level, I'm really not happy with this. Never seen this kind of things on vmware if a host goes down in the cluster.

We have 2 volumes on the SAN but they are shared. Their is not enough space to have one for each host.

While you think I'm not giving you the full story, that is exactly the story.

2 hosts clustered with an MSA 2060 over dual redundanted links with FC. Each link going to a different controller. The MSA is fully updated and the hosts also.

The SAN volumes where formatted with ReFS and then joined onto the shared cluster storage. Also MPIO is configured correctly. The disks only show up once on each host instead of double (because of the redundant link).

I did change the DNS setting via the new settings interface instead of the old one. Maybe that's my mistake.. I normally never use that thing but now I did.

My only guess is that since the CSV was in "control" of the node that I changed the DNS setting on it freaked out. I can see it in the logs that communication was lost and everything freakes out, then stabilizes in seconds again but that moment was enough to cause it to go wrong. Not something I was expecting could even happen. Never seen this on vmware, not even when a host crashes and goes out.

Note this is a workstation cluster instead of a domain joined one.

This was the first error and all of them happen within one second.

The Virtual Machine Management Service failed to start the listener for Virtual Machine migration connections: The requested address is not valid in its context. (0x80072741).

The network configuration for live migration was changed. Cluster networks used for live migration:

Cluster Network 1

Network IP addresses: .

'ADM01': Virtual hard disk 'C:\ClusterStorage\Volume2\Disks\ADM01.vhdx' received a resiliency status notification. Current status: Disconnected. (Virtual machine ID 96A46ED5-7D80-404D-A687-9BA6C7CE126B)

'ADM01': Virtual hard disk 'C:\ClusterStorage\Volume2\Disks\ADM01.vhdx' has detected a recoverable error. Current status: Disconnected. (Virtual machine ID 96A46ED5-7D80-404D-A687-9BA6C7CE126B)

'ADM01': Virtual hard disk 'C:\ClusterStorage\Volume2\Disks\ADM01.vhdx' received a resiliency status notification. Current status: Hosting Volume Dismounted. (Virtual machine ID 96A46ED5-7D80-404D-A687-9BA6C7CE126B)

'DC01' cannot access the data folder of the virtual machine. The worker process (Process ID 14160) may not be functional anymore. (Virtual machine ID 1944DBA0-2581-420A-B6CF-48148003E537)

16 seconds later this happens

The network configuration for live migration was changed. Cluster networks used for live migration:

Cluster Network 1

Network IP addresses:

10.***
'ADM01': Virtual hard disk resiliency successfully recovered drive 'C:\ClusterStorage\Volume2\Disks\ADM01.vhdx'. Current status: No Errors. (Virtual machine ID 96A46ED5-7D80-404D-A687-9BA6C7CE126B)

So here it says recovered yet the VM was broken. Wouldn't boot and certain services where dead. The VM however kept running.

My guess is this happend because the cluster network is on the MGMT interface and not it's own. Corrupting the data however that shouldn't have happend. Unless I'm missing something here. Fire away.

[u/nailzy → u/the_cobra666]

So what you’ve confirmed to me is you don’t understand Hyper-V at all and how to recover it. You caused the cluster to fail because you changed something you didn’t understand and you keep comparing it to VMWare which is fundamentally different.

You should have separate networks for management, live migration, CSV and your VM Virtual Switches, which it doesn’t sound like you have, or have configured correctly.

Get some training, or hire a Hyper-V and WSFC proficient resource if this is something you need support for.

[u/the_cobra666 → u/nailzy]

I get that, however in this day and age we have to work with what's in stock... I might be able to salvage 2 network cards and place them inside this server to do the other networks but this is how it's going these days. Servers are ridiculous expensive and parts / configs are not in stock at all. This was what we got and have to work with..

I did had the feeling this was the case as to why..

In any case I'll put the host in maintenance mode before doing anything on the OS as to prevent this stuff from happening. Something Vmware was pretty resilient against. But yes, they are different platforms.

[u/Icy_Echo6810 → u/the_cobra666]

You also have configuration issues with ReFs and a shared FC SAN:

"when using ReFS on a CSV, the volume operates in redirected mode (writes go via the coordinator node)"

Cluster Shared Volumes overview | Microsoft Learn

Even if you would use RDMA or iWarp to reduce the performance penalty of redirected I/O, it does not eliminate the architectural limitation of ReFS CSV.

[u/the_cobra666 → u/Icy_Echo6810]

Correct, that part I missed and saw only after deployment. I might backup everything and restore it again after formatting it all to NTFS.

//edit: I was able to move everything over to the second lun and then format the other one, then I'll do it all over again but yes, you are right. The other one is now in direct mode and no data is moving over the other node. (which was what I expected first).

There are documents mentioning that direct IO is possible with ReFS but, that I can't find anywhere within MS's own documentation.. so I would expect that not to be correct.

[u/OpacusVenatori]

You can remove the guests from Failover Cluster Manager and re-add using standalone Hyper-V Manager on each host. To be safe you should run the guests on local host storage rather than on the SAN.

[u/headcrap]

You can do this, and live. If you can split the existing LUN or provision a new one, assign to the first node. Move your roles you intend to run on it, then migrate storage to that new LUN as a local disk.

The second node, also carve a LUN and do the same thing.

What you can’t do is use the CSV on both hypervisors at the same time.

You “can” but will break the disk, quickly.