AMD is releasing a 6 Core Opteron processor. Hyper-V in Windows Server 2008 R2 will be fully able to take advantage of that:
- There is support for 64 logical processors or physical processor cores
- With support for 8 virtual processors per physical core, that’s 512 virtual processors that you can have on a single host
- There is support for up to 384 running virtual machines per host.
Those are some pretty wild numbers. You’d probably need to push your RAM up to the supported limit of 1TB. In a 3 host cluster you could be running 768 virtual machines with host fault tolerance.
I’ve been involved in an online discussion about the merits and scalability of Hyper-V versus ESX. These numbers came up. As one guy correctly pointed out, these are purely theoretical numbers for most of us. When you start looking at network cards, storage HBA’s and bandwidth then you really want multiples of connections per server when dealing with that many VM’s per host.
The other preventing factor is RAM costs. I found the sweet spot for a host server was 32GB RAM. Once I looked at putting 64GB in the price jumped exponentially. Virtualisation at those levels isn’t quite as cost effective.
So yes, Hyper-V in 2008 R2 has huge scalability but for 99% of us, that’s not going to matter for quite some time.