Existing Hyper to Hyper-V cluster without downtime

Question

hi to all,

got a hard question to HyperV gurus. The customer has 2 HyperV servers running lost of virtual machine inside on a storage lun.
The luns are not shared between the HyperV servers.What i try to say is , 2 servers has 2 different luns attached ,and the virtual machines lives on those luns.

We need to migrate this environment to HyperVcluster (hyperv failover cluster ) , can this be completed without down time??
I read some articles but i am not sure ,

Theorically , we need to add failover cluster component to the servers, and then make the luns shared between HyperV servers ,and confiure the clustering wizard stuff.
but since the luns has servers inside, what is the aspect of running the failover clustering setup wizard on them??

if someone can tell their stories or any articles it will be great

thanks

Answer 1

Hi,
You thought can be realized.
I did test below:

1. Firstly, create a VM on standalone Hyper V host, store the VM on a non-shared location:
   
2. Then create a Cluster with the two Hyper V hosts and configure shared storage for the Cluster, add shared storage to the Cluster as CSV.
3. Move storage of the VM to a CSV:
   

during the migration, the VM doesn't have downtime.
4. After migrating the VM storage to the CSV, we can add the VM to the cluster:

Thanks for your time! If you have any other concerns or questions, please feel free to feedback.
Best Regards,
Anne

Answer 2

I don't think you will be able to perform a build of a cluster and import of the VMs without some downtime. Windows Server 2019 does allow adding of the cluster feature to a server without a reboot. And you can define access to additional LUNs without a reboot. But the location of the VM files changes when you move them from local storage to cluster storage. When you have a VM defined on a local machine, you have it defined as something like D:\vms\vmname.vhdx. When you move them into a cluster, the location changes to something like C:\Clusterstorage\disk1\vmname.vhdx.

It would be better to just plan to perform the reconfiguration and migration during a maintenance period.

Answer 3

Thanks a lot Tim,

so from your answer , i thought something like this.BEside of adding existing luns to failover cluster, create new luns from storage and then add those luns to failover cluster.

during that period ,the virtual machines keeps on running, and after the setup finshed ,i can move the virtual machines from local storage to the cluster while they are powered on

How does this sound???

Answer 4

Version of Windows Server is not mentioned. I believe this is possible with 2019 because installation of the cluster feature does not force a reboot of the host. I know some earlier versions did require a reboot of the host after the cluster feature was added to the host.

Answer 5

Thanks a lot for all your time and answers .

2019 server also needs to reboot when i add Failover Clustering role , to bad :(

also XiaoweiHe-MSFT , your answer seems OK ,i will try to do it in my lab environment.

anyway thanks a lot either of you ,:)