Vmware CPU Sizing

[aetius1980]

Hi,

I have a current Vmware environment running on slightly older blades. My environment hosts around 100 virtual machines that have grown over a period of time.

I'm now looking to condense these vms down to a 1/3 or 1/4 with higher spec virtual machines. My current VMs aren't particularly CPU intensive.

I'll be going from hosts with 40 cores to newer hosts with marginally better CPUs with 20 cores.

Please advise how I can get my sizing right.

Thanks

[weinstein5]

MOst accurate way is to do an assessment of you resource utilization by you existing VMs but if this is not possible then you can use this to estimate your environment With vSphere 5 you safely can12-14 vCPU per core -

[aetius1980]

Hi Weinstein,

In the current environment I have the virtual machine cpu load average and peak, as well as the host's CPU specifications.

Is it as simple as saying if my current environment is

16  core intel xeon server

running 32 virtual machines with 4 cores each

Each virtual machine has an average and peak CPU utilization of 10%

I can then safely transfer this to

8 core intel Xeron server

running 16 virtual machines (I'm looking at consolidating vms)

Each virtual machine runs at average and peak CPU utilization of 40% (i.e. doubled as the number of servers are halved, plus I'm running on fewer host cores, so doubled again)

?

Bear in mind the host CPUs are roughly equal

Thanks

[weinstein5]

First question - You indicate that you have "32 virtual machines with 4 cores each"  - do you mean that each vm has 4 vCPU? If so this is probably overkill on cpu resources for the VMs - you should always start with a single vcpu for your vms and add vcpus only is needed - I think there will be a potential impact to performance if you maintain the quad vcpu VMs in the environment - you should have now issues if you drop the VMs to a single bCPU with no to little impact to the VMs performance -