I looked through alot of documentation on best practices for memory and cpu for ESX and guest VM's. Is there any documentation out there that specifically states how many VM's an ESX host can handle based on how many processors the host has?
I've been trying to explain this to my manager and he just looks at me all glazed over. If there is a document out there that specifically tells you how many VMs you can have per host that would be great. Or a tool I can run for sizing our environment.
They think it works just like a physical server and I am trying to build my case against not making everything in our environment a VM. Just because you can doesn't mean that you should and now I am running into VM sprawl.
Any help would be appreciated.
A general rule of thumb is 4 VM's per processor core, of course this will vary based on what is running on the VM's. You can get as much as 6-8 VM's per processor core on lightly used servers like webs servers and as few as 1-2 VM's per processor core on heavier used servers like SQL and Exchange. Check out these links...
ESX Workload Analysis: Lessons Learned - http://download3.vmware.com/vmworld/2006/adc9398.pdf
Getting the Right Fit: VMware ESX Workload Analysis - http://download3.vmware.com/vmworld/2005/sln056.pdf
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As Eric says a good general rule of thumb for basic sizing is 4 vCPU guest VM's per physical processor core.
for a more through rough guide utilse the VMware Sizer on the HP site
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