Can we build a Hyper V failover cluster without a SAN or other shared storage?

Question

I have a question about Hyper-V Failover Cluster. I have 2 server Hyper-V and want to use a failover cluster. As far as I know, I need a SAN server for that, so do we need it in here?

Solution 1

Windows Failover Clustering (which is what Hyper-V uses for clustering) requires shared storage of some sort.

Further to Massimo's answer, and if I'm reading this page right, I don't think you can use exclusively SMB shares for a failover cluster.

You'd still need some shared disks (SAS, iSCSI, FC) for the cluster portion, but you can store the Hyper-V VM files on SMB shares.

Solution 2

This is not a direct answer to your question, just a brief list of some potential alternatives.

As others have said, if you don't have shared storage there's no point in having a failover cluster. You do have the option of shared-nothing live migration. You can freely move your virtual machines between hosts, provided you have the resources to do so, without shutting them down.

Another option if you have plenty of storage, is Hyper-V replica. Depending on your requirements and the failure scenarios you have discussed, the Hyper-V replica could get you close. Hyper-V replica is not a replacement for failover clustering, but it offers you an almost up-to-date replica of the live VM that can easily be brought online in the event of a catastrophe. You can do planned and unplanned failovers. It's designed for DR situations.

Either way, there are technoloiges available that will get you most of the way to failover clustering without a SAN. The best solution would be to make a SAN or shared storage available if your requirements warrant it.

Comments

[Todd Wilcox]

Note that building a failover cluster without using resilient shared storage is pointless, except as an exercise. The idea behind a failover cluster is if one host goes down, the other(s) can bring up the VMs and they can stay up. If the shared storage goes down, the hosts have no access to the data needed for the VMs, so all the VMs will go down even with both hosts up. So whatever shared storage you use should be as resilient as possible. Redundant network paths between hosts and storage is also a good idea.

[kasperd]

This answer could do with some improvement. For example it is unclear which part of the question "Yes" is supposed to apply to.

[GregL]

There's only one question asked here and I'm answering it pretty definitively.

[kasperd]

The subject asks if the setup can be build without a SAN. The last sentence of the question asks if a SAN is needed. It does make a difference whether the "Yes" applies to one or the other.

[GregL]

When I answered, the subject wasn't as clear as it is now, and having opposing questions in the subject and body makes things confusing. Either way, I'll edit my answer to make it more obvious.

[Todd Wilcox]

Your point about SMB is a good one, although I wonder if a failover cluster for Hyper-V that doesn't need a witness disk (odd number of hosts) needs non-SMB 3.0 shared storage.

[GregL]

Yeah, that would probably work!