Vmware > Hyper-v Migration
Posted by Aggressive_Common_48@reddit | sysadmin | View on Reddit | 26 comments
We’ve reached a point where K-12 can’t afford new hardware, but we still need to migrate from VMware to Hyper-V across our six ESXi hosts. We’re currently using Pure Storage for data, with about 55% utilization on both nodes (Cluster 1: 3 ESXi hosts → Pure Storage Node 1, Cluster 2: 3 ESXi hosts → Pure Storage Node 2).
In total, we’re running around 50 VMs, including roughly 20 critical ones. I’ve been tasked with leading this migration, and we need to make it work using our existing hardware and storage.
Has anyone handled a similar situation? How did you approach the project? Did you start by repurposing one host—installing Windows Server 2025 Datacenter, setting up Hyper-V, and building a failover cluster first—or did you migrate hosts individually and form the cluster afterward?
DarkAlman@reddit
Do an assessment first to confirm that you have enough capacity to take 2 of the VMware servers offline and that all the VMs are compatible with Hyper-V.
Rebuild 2 of the Servers as Hyper-V nodes and setup the clustering.
Present new Storage LUNs to your Hyper-V servers as the VMware LUNs aren't compatible.
Convert over your VMs in batches. As resources get freed up you can decom the next VMware server and convert it to Hyper-V and continue the process.
Veeam is the best method I've found to convert the VMs. You can do an instant-on recovery from a VMware backup to Hyper-V direct from your backup storage, then trigger a Storage VMotion in Hyper-V to move the data to your live storage.
This is a lot better that sitting there for hours per VM waiting for the conversion utility to move over all the blocks 1 at a time.
If you need a conversion utility Starwind has a free one and it's pretty good.
The most complex part is managing the RAM and Hard drive usage between the two cluster during the conversion.
And don't forget that you'll need a complete new backup routine once a VM is converted over.
arkaine101@reddit
I uninstalled VMware Tools prior to migration. I think it was something like this:
DarkAlman@reddit
Depending on the network adapter type used uninstalling the VMware tools may cause the source VM to lose access to the network, so be careful with this approach.
excitedsolutions@reddit
If you don’t uninstall VMware tools in the Vm prior to migrating the VM, VMWare Tools cannot be uninstalled normally. You can’t use add/remove programs to uninstall and have to use a 3rd party script to remove.
Aggressive_Common_48@reddit (OP)
It helps a lot. Thank you so much. I really appreciate it
joeykins82@reddit
I would consolidate your ESXi deployment down to a single 4 node cluster (if possible), or to 2x 2 node clusters so that you can build a 2 node Hyper-V cluster. As you move VMs over you can decom 1 ESXi node, rebuild it with WinSvr, and add it to the Hyper-V cluster until all 6 hosts have been rolled.
You will need a Domain Controller running outside of your Hyper-V cluster and for all hypervisor hosts to use something other than their own VMs for DNS resolution: if you don't do this then if your cluster ever fully goes down you will have created a circular dependency where the cluster cannot come back online without Active Directory, but AD is down because your DCs are VMs which depend on the Hyper-V cluster.
vayn0r@reddit
I'm of the school of thought to not join your Hyper-V hosts to the domain as well.
DarkAlman@reddit
You need them to be AD joined to setup a proper cluster
BatemansChainsaw@reddit
They can be their own separate domain
DarkAlman@reddit
Which may or may not be practical depending on the size of your environment.
BatemansChainsaw@reddit
your comment doesn't make sense.
Even in a two node cluster it's practical.
Zealousideal_Fly8402@reddit
Server 2025 supports Workgroup Clusters.
topher358@reddit
Supporting it and it being a good idea are two different things. We tested this extensively late last year and there are just too many small issues with work group clusters to make it worthwhile. A dedicated hyper V domain is the way to go with at least one domain controller outside of the cluster. Either on local storage or a physical box of its own.
joeykins82@reddit
How are you planning to cluster them without AD?
Jawb0nz@reddit
True. My normal method is to run the environment entirely virtually, leaving hosts as workgroup machines only. It helps reduce damage footprint, IF the local admin isn't the same pw as domain.
But to cluster, you're right that they need to be domain joined.
joeykins82@reddit
When you hit a certain size an infrastructure forest has definite value. In OP's case though they're not at that point.
vayn0r@reddit
Well, that is true about the clustering. It's more from a security standpoint that I prefer to keep hosts off the domain, but a separate domain for clustering would also work.
RedGobboRebel@reddit
I'd instead suggest setting up a separate management domain for the hosts instead of running them all stand alone. If you don't setup a forest or trust relationship with your primary domain, then you can keep any access for hosts and VMs completely seperate.
INSPECTOR99@reddit
Get a mid-level server box to ONLY host Active Directory AND 10 TB high speed storage. This can relieve much valuable resources on your existing server structure while probably offering a modicum of performance boost.
Aggressive_Common_48@reddit (OP)
Yes. My plan would be to create a new LUN in pure storage, evacuate one node from each cluster , set them up with hyper-v on windows 2025 , configure networks and csv , create a cluster and then start migrating from each node from esxi clusters.
SudoZenWizz@reddit
I've been using for migration from esx to hyper-v veeam backup and replication with minimal downtime.
Starting with reinstalling one host and start migrating on it.
for easier setup and verifications we have in-place monitoring with checkmk with integration to esxi and hyper-v and also with agent on all vms. after migration we checked the status in monitoring: la green: move further with next one.
links_revenge@reddit
Went through this last year knowing we weren't renewing VMware this year.
Had a spare box and installed H-V on it, attached it to the NAS. Used starwinds converter for the most part which worked great. Also had the ability to pull a full backup in vhdx format if needed.
When one host was empty, I converted that to H-V and made a 2 node cluster. Continued draining hosts and converting as I went, expanding the cluster.
Besides for the (re) learning curve, it was pretty painless. Time consuming, but not fighting to get things working.
SperatiParati@reddit
We're 75% of the way through migration of approximately 600 VMs across 30 hosts across 2 Datacentre.
We started by putting 2 hosts in maintenance mode and rebuilding them as Server 2025 and starting a cluster from the outset.
They are joined into an infrastructure domain, which also has two physical domain controllers (one per DC) to allow for bootstrapping.
ComfortableAd7397@reddit
We build the new cluster with new hw and HV, then with veeam made a 'failover migration' host by host. Not a single fail in the 37 vms migrated.
Aggressive_Common_48@reddit (OP)
It was my initial plan and it would have made even easier but there's no point that we can afford new hardware as per the management and I have to stick with the existing environment.
_Birdman_2000@reddit
I would make a cluster first. Test and validate fail over. Then work on migration.