VMware vSphere

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  • 1.  High cpu usage or not?

    Posted Jun 03, 2011 06:32 AM
    Using ESX4.1
    On a couple of Windows 2000/2003 VM's that have been P2V'ed a while ago, the guest OS shows minimal (6% avg) cpu usage, but the performance charts show it goes up to 98% with an average of 51%.
    The VM has 4vCPU's, as i think it was a straight P2V with no changes to the destination.
    VMware tools is installed and up to date. VM's are running version 7 hardware.
    Just not sure why vCenter is reporting different usage to the guest OS.
    Perfmon shows different amounts for Processor Time\Processor to Processor Time\VM Processor. [I'm guessing VM Processor is x4 due to 4vCPU's]
    Quite often DRS moves these VM's around the most, many times per day. They used to suffer from high CPU Ready times before i reduced other VM's to lesser vCPU's, but those were shown to be using less cpu.
    The admins of the VM's are reluctant to downsize (of course!). It's hard to know which cpu usage is right. But i find it hard to believe a Windows 2000 box could be using over 10Ghz of CPU!
    Any tips?



  • 2.  RE: High cpu usage or not?

    Posted Jun 03, 2011 07:52 AM

    showing point in time snapshot may not be accurate. i would advise looking into vcenter's history usage for 1 month or 1 week and from there you have more solid facts to down size. another way is to install a trial of capacity IQ and let the software intelligently advise you on the downsizing configurations.