Maximum configuration Magic :)

Maximum Virtual CPU’s Per Host :512

Maximum Virtual Machines per Host:320

So how many 2 SMP per host we build ?

=> it is 256 Dual Processor VM’s we can host. 512 is maximum if we want 2 we have 512/2=256

So maximum 2 SMP VM’s would be 256 only

Accordingly 4 SMP VM’s would 512/4 i.e.128 only

Accordingly 8 SMP VM’s would 512/8 i.e.64 only

In all cases vCPU count is limiting factor, actually 320 limit of virtual machine per host is not even reached by that logic.

Now why this is important as these calculation only meant per/host. As you start increasing your cluster, your failover capacity could be easily calculated using above information

Maximum Virtual Machines per core is 25

Maximum Virtual Machines per Host:320 this means you can full utilize only upto 12 cores (320/25), IF your virtual machines are going to cross 320 limits.

So in enterprise environment with less than 8 node cluster, you can only have 160 virtual machines per host. So above mentioned 320 VM’s/host limit get reduced by 50%, the moment we decide to make it cluster. So now if we’ve 160 VM, we will need a server with 160/25=6.4 or approx 8 cores. So assuming we will be continuously expanding our vSphere infrastructure we should always buy server with more than 8 cores. if you buy anything else your total number of vm per host will be limited.


DISCLAIMER: This is all around configuration maximum or limit. As general design practice, never touch these limits

By Preetam Posted in vcp40

One comment on “Maximum configuration Magic :)

  1. Pingback: Few thoughts on Cluster size « Designing vSphere

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