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Yeah, I knew the "it depends" answer was comming up 
But what would your gut feeling be? When talking about 30 VMs on one host, I'm proud we can achieve these results, when talking about 60, I get a bit scared about uptime.
http://www.GabesVirtualWorld.com
But what would your gut feeling be? When talking about 30 VMs on one host, I'm proud we can achieve these results, when talking about 60, I get a bit scared about uptime.
http://www.GabesVirtualWorld.com
My gut feeling ... no more than ~30 VMs per host.
This way failover capacity isn't too expensive, management isn't a nightmare and
you don't risk your job when a host goes down 
This way failover capacity isn't too expensive, management isn't a nightmare and
you don't risk your job when a host goes down
My heart says go with as many vms on the host as you can get, my head says 30 is probably close to the limit, I would look for a sweet spot for price and number of vms per host. so maybe 40 vms pers host would be more cost effective and not quite as bad as 60vms failing at once and better than 30 vms.
I would love to see 50 or 60 vms running on each host in a cluster, if you can find the capacity to satisfy failover I say go for it!
Just hope 2 hosts don't fail at once!
the larget box I have seen is the DL580G4 with 4 quad cores
Then you should take a look at the HP DL785G5 - eight AMD quad-core CPUs.
Not sure though if this beast is on the HCL.
I make this decision based on a couple things:
So, there's not single "right" answer (other than "it depends")
Ken Cline
Technical Director, Virtualization
Wells Landers
VMware Communities User Moderator
- - How important are the VMs in questions?
- If they're truly "mission critical", then I keep the number small - on the order of 10:1
- If they're "important", then let's look at 20:1
- If they're "who cares if they're up", then load 'em up!
- - How large is the environment? I like to deploy a minimum of two hosts (three makes me happier)
- 20 systems @ 2 hosts = 10:1, @ 3 hosts = 7:1
- 100 systems @ 2 hosts = I wouldn't do it, @ 3 hosts = 34:1
- 1,000 systems - now you're talking! @ 20 hosts = 50:1, @ 30 hosts = 34:1, @ 20 hosts = 50:1, @ 10 hosts = 100:1
- 10,000 systems - you can bet I'm going to have a few hosts with 50 to 60 (or more) VMs and some hosts with 10 (or less) VMs!
So, there's not single "right" answer (other than "it depends")
Ken Cline
Technical Director, Virtualization
Wells Landers
VMware Communities User Moderator
