KVM Limits

GarthK

Member
Feb 7, 2009
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All,

I work for a company that develops and sells Windows-based software. I currently run an ESXi v4 box that is a dual quad-core Xeon with 32GB and a few TBs of DAS. It is currently running a collection of Windows Server 2003 and 2008, both 32 and 64 bit, a large number of XP VMs, and a fair number of Win 7 32 and 64 bit boxes. All VMs run continuously. The total number adds up to 47 at the moment. The system idles at about 17% CPU in the morning and that will pick up during the day sometimes peaking up near 50% for short periods. There are issues with ESXi datastore size on DAS that are pushing me in the direction of using NFS over the wire, something I would prefer to avoid.

Finally, my question: Do you think that the pure KVM config (no OpenVZ) would handle such a load? I know you need more info but I'm not looking for details, just an initial reaction.

Thanx,
Garth
 
Let me rephrase to a more reasonable question. What I am looking for are real-world experiences of running Windows VMs on kvm; how many, how big, how busy. Do you overcommit memory? CPUs? Disk space? I intend to do some serious testing but some initial advice would be welcome.

Thanx,
Garth
 
Let me rephrase to a more reasonable question. What I am looking for are real-world experiences of running Windows VMs on kvm; how many, how big, how busy. Do you overcommit memory? CPUs? Disk space? I intend to do some serious testing but some initial advice would be welcome.

Thanx,
Garth
Hi,
i'm lucky and don't have such a lot of windows guests... ;)
but i don't do memory overcommitment - in this case you can't start all machines at the same time if you get trouble and the server must be rebootet (after a short time KSM should get enough free mem to start all, but memory is not so expensive...).

I have made good experiences with kvm - but it's depends on your usage. If your guests do high IO they need more CPU (i think more CPU than under vmware). With only one guest-cpu the io-rates are much higher than you get with vmware. Also the booting of the clients goes a lot faster...
I think it's the best you give proxmox a try - and please wrote about your experiences.

Udo