Check out this topic on the VMTN forum by Gabrie. It’s a good read about how many vm’s one would dare to run on an ESX host.
TexiWill:
This really depends. I know companies that are doing no more than a 10:1 or 20:1 compression, but there are other companies with 50+ VMs running on one box (at the time it was a DL760 with 8 CPUs and 64GBs of memory. I do know that the max vCPUs you can put on a system is still 8 * pCores and the larget box I have seen is the DL580G4 with 4 quad cores (16 cores) and 512GBs of memory….. So maximally 128 vCPUs…..
Ken.Cline:
I make this decision based on a couple things:* – 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”)
vSphere 4.0 Quick Start Guide
As mentioned I think it comes down to a few things.
How powerful is your host as far as resources.
What type of applications?
How many eggs do you want in a basket?
For us we tend to go more on load percentage than a hard number. In our non-production environments we will go higher load percentage. In our production environment we try to keep it fairly low, around 50-60% load. This allows us to have room for resource spikes as well as the ability to lose more hardware.
It all comes down to risk assessment.