1 Reply Latest reply on Oct 3, 2010 12:14 PM by ScottBentley

    What will I lose with EVC?

    thomps01 Hot Shot

      I have a number of HP DL380 G5's, a DL580 G5 and some DL380 G6's. The processors I'm using are 73xx, 53xx & 55xx


      I'm wondering, should I create a seperate cluster for G5 and G6's or just dump them all in 1 cluster.


      I know that if I enable EVC and set this to Intel Core 2, each of the above hosts should sit happily in the same cluster.


      The thing is, I'm not sure what I'll lose in terms of capabilities from the new G6 hosts.


      Option 1 - Create a single cluster, enable EVC and lose the advanced features of G6's (not sure what these are and if I'll notice)

      Option 2 - Create 2 clusters, but will essentially lose a host in each cluster to HA redundancy.


      Does anyone know if there are any significant negative side effects which I'll encounter by enable EVC at the Intel Core 2 level?


      Thanks in advance

        • 1. Re: What will I lose with EVC?
          ScottBentley Expert


          Most of the time you should not see any performance loss



          Quotation taken from the following document http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1005764#performance



          If I add newer hardware into an EVC-enabled cluster with a lower EVC mode, do I lose performance?  

          All CPU features provided by your host hardware are available to the hypervisor. Optimizations for CPU virtualization such as AMD-V and Intel VT-x or facilities for MMU virtualization such as AMD RVI or Intel EPT support are still used by the hypervisor. Only those CPU instructions that are unique to the new CPU are hidden from virtual machines when the host joins the EVC-enabled cluster. Typically this includes new SIMD instructions, such as the latest SSE additions. It is possible, but unlikely, that an application running in a virtual machine would benefit from these features, and that the application performance would be lower as the result of using an EVC mode that does not include the features. Check with the application vendor to determine which CPU features are used by the applicatin.



          I hope this helps



          1 person found this helpful