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2922 Views 5 Replies Latest reply: Jun 25, 2012 8:44 AM by thedada RSS
thedada Rank: White Belt 14 posts since
May 16, 2012
Currently Being Moderated

May 16, 2012 8:16 AM

Weird Results with Virtualized CPU monitoring

Hi there !!

 

I just started with some tests with zenoss.

My VM's test run on KVM Hyperviseur  related to a Cloudstack Server.

 

I settle up a simple snmp monitoring for basics check first .

All was good and the graph looked nice but when I tried stressing the cpu (with a stress --cpu 10 --timout 30 for example) and watching locally my CPU % Use (100% for the stressed time) I can only see some 20-30 % use on the zenoss graphs.

 

I tried stressing more but on the graph, it never reached the 100%.

 

I tried to figoured out how this monitoring works, and it's just some simple snmp trap ( I dident tried with a SSH monitoring yet )

 

Did someone already have the same results ?

 

 

Ty for your time.

 

Cheers.

  • Rank: Green Belt 70 posts since
    Jan 24, 2012
    Currently Being Moderated
    1. May 30, 2012 12:47 AM (in response to thedada)
    Re: Weird Results with Virtualized CPU monitoring

    For each measurement, are you measuring within the (K)VM or on the host? Can you post the specific commands you are using to determine CPU usage?


    Thanks

  • Rank: Green Belt 70 posts since
    Jan 24, 2012
    Currently Being Moderated
    3. Jun 4, 2012 12:50 PM (in response to thedada)
    Re: Weird Results with Virtualized CPU monitoring

    If you are looking at "top" on the host, then the CPU may in fact be saturated inside the VM. The VM may only have one of your cores and that would explain why it cannot saturate the host's CPU -- it only has "a piece" of it.

     

    Be sure to compare "top" inside the VM and on the host, and also compare "cat /proc/cpuinfo | grep -c ^processor" on the host and inside the VM. This will show you how many cores are inside the VM vs. the host.

     

    The CloudStack ZenPack should make this a bit more clear, I think.

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