3

Possible Duplicate:
Can you help me with my software licensing question?

when a server has more than 8 cores per CPU (total 16 logical procs) and ESX standard license is applied, what does it mean for VM performance? Since each VM on host is allowed only 4 vCPUs max

VMWare ESX/ESXi limits the no of vCPUs per guest VM depending on the license:

standard Lic = 4 vCPU Advanced Lic = >4 since i dont know exact number

is there need to upgrade to Advanced version for any perf benefits if none of VMs have workloads that need more than 4 vCPUs?

Community
  • 1
JMS77
  • 1,275
  • 5
  • 27
  • 44

1 Answers1

3

HERE is a handy guide to the various capabilities based on licence type - as you can see only Enterprise Plus (not Advanced) supports >4-way vSMP (specifically 8 with 4.0U1). And to answer your question - only ever give a VM what it needs, never any more - adding more is likely to actually slow down your VM.

Chopper3
  • 100,240
  • 9
  • 106
  • 238
  • 2
    Adding additional CPUs will only slow the machine down when there is CPU contention and there are not enough cores to fulfill the request. Folks familiar with esx 2.0 were always told 1 cpu per vm. 3.x changed to “relaxed coscheduling" so this problem went away (http://www.yellow-bricks.com/2008/07/07/multiple-virtual-cpu-vms/) On systems with lots of processes you should default to allocating 2 CPUs. Citrix farms are a good example of this (http://virtualfuture.info/2009/03/citrix-xenapp-on-vmware-esx-1-or-2-vcpu/) Adding an additional extra CPU shouldn't degrade performance (YMMV) – Jim B Jun 07 '10 at 15:20