VMware vSphere

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  • 1.  adding and editing number of CPU

    Posted Feb 02, 2011 01:31 PM

    Hi

    I have few VMs and they were imported directly from the physical to virtual. Now they have the same number of cpu as they were in physical ( 4 cpu ), this is limiting my ability to put the vms in HA cluster. could i just edit the cpu and change total cpu to 1 ? it is advisable or any negative impact ? and in case if i experience any performance issue would like to add more cpu, any issues that i could expect here ?

    Thx



  • 2.  RE: adding and editing number of CPU

    Posted Feb 02, 2011 01:43 PM

    depending on the Guest OS, you would have to power down the guest in question to reduce/add CPU.  Also, for Windows OS's, ensure you have checked there correct HAL is installed.

    But, yes, a good rule of thumb is to start with 1 vCPU and go from there, and adjust up if needed.



  • 3.  RE: adding and editing number of CPU

    Posted Feb 02, 2011 01:48 PM

    Hello.

    What OS are you talking about here?  The number of vCPUs isn't necessarily limiting your ability to put VMs into the HA cluster.  What is the size of your cluster and what CPU resources do you have in the hosts?

    You can change the number of vCPUs farily easily either way.  Windows 2008 requires no additional work, where earlier versions should also have the HAL changed if you were to go to a single vCPU.  You will likely see performance gains from reducing the number of vCPUs, but I say this generally without knowing your workloads or host capabilities.

    Good Luck!



  • 4.  RE: adding and editing number of CPU

    Posted Feb 02, 2011 02:59 PM

    the os is windows 2003 with sp3. i would like to enabled FT on the cluster. adding / removing how the HAL get adjusted ? do I need to do it manualy or it get adjusted automtically when i restrt with changes ? what type of impact i could expect ?

    thx



  • 5.  RE: adding and editing number of CPU
    Best Answer

    Posted Feb 02, 2011 03:02 PM

    within device manager click on the plus sign by computer, and you should be using a uniproccesor hal

    http://support.microsoft.com/kb/309283

    Also, keep in mind FT only supports 1vCPU guests.



  • 6.  RE: adding and editing number of CPU

    Posted Feb 02, 2011 03:03 PM

    You would have to modify it through device manager.  Here is a KB with some information that may help, http://kb.vmware.com/kb/1003978.    I would also do some searching around the forum for information and experiences.