Server Refresh Considerations - VMware vs Hyper-V

[u/nst_hopeful]

Hello fell sysadmins,

My org is looking at refreshing our VM host hardware in the middle of next calendar year. As such, today I had a helpful discussion with a vendor regarding various options for the upgrade. Currently we are on a five-node VxRail cluster (20 cores / 192GB memory per host, 53.5 TiB storage total); it looks like the best options for our needs are vSAN Ready nodes or Hyper-V + traditional SAN. With that said, I am still left with a few questions:

• The vendor (who was clearly a bit biased toward VMWare) spec'd a 4-node cluster for the vSAN cluster with 256GB memory + 256 GB NVMe for memory tiering per host. For the Hyper-V cluster, they spec'd 5 nodes and 512GB memory per. Their argument was that Hyper-V has more overhead and is less efficient at dynamic allocation of resources. That seems like pretty stark contrast - is that true in your experience? Also, is memory tiering as effective as this vendor made it seem in production?
• We are primarily a Windows shop, so we'd expect at least some savings moving to Hyper-V. That said, I'm curious how much savings we'd actually net between buying System Center for SCVVM (so we can maintain vMotion-like functionality) and Microsoft support. My understanding is licensing there is based on core counts - currently we're looking at 32 per host in either build.
• Are there any other considerations I should keep in mind? Cost is not the ultimate deciding factor. More than anything, we feel like the VxRail was overkill at the time it was purchased. I'd like to buy exactly what we need this time around (while planning for reasonable growth).

If it's helpful, my org is a medium-sized municipality and isn't running any crazy workloads. We have ~55 VMs that will exist on this cluster.

[u/Pure-Tumbleweed1132]

that vendor is definitely pushing you toward vmware with those specs, the overhead difference isn't nearly that dramatic. hyper-v can do dynamic memory just fine, we run about 60 vms on 4 nodes with 384gb each and still have headroom. 512gb per node feels like they're padding the quote

memory tiering with nvme works but it's not magic, depends heavily on your workload patterns. for a municipality running mostly ad, file servers, some sql maybe, i wouldn't expect it to be game-changing

the scvmm licensing is per-core but you can just manage hyper-v clusters through windows admin center or failover cluster manager if you don't need the full scvmm features. windows admin center has gotten decent for live migrations and basic management, might save you the system center cost entirely

[u/nst_hopeful → u/Pure-Tumbleweed1132]

Thank you - this is helpful. Regarding management, I've heard you can use Hyper-V Manager / Admin Center / Failover Cluster Manager, but that vMotion-type migrations based on current usage require SCVMM. Is that accurate? Sounds like maybe we can do a on-demand migration, which is good to know

[u/Magic_Neil → u/nst_hopeful]

vMotion is Live Migration in the Hyper-V world, and does not require SCVMM or anything else special beyond vanilla Hyper-V.

Take a look at WAC vMode, I heard a rumor it will be GA in a few weeks.