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Aloosh
Contributor
Contributor

CPU Usage in VM different to VC CPU graphs

We have recently depolved a new DEV environment on two 4way DualCore Opteron servers. At the moment these servers are not doing anything and report between 0-5%CPU usage in Task manager. When I open up Virtual Center I see the CPU usage hovering up above/near the 90% mark for all the VMs but the Memory, Disk and Network are a flat line near the zero mark. Im assuming I have made a mistake configuring VC but cannot figure out what. There are 4 VMs per box and are bog standard win2k3 SP1 installations with no other software installed.

Any help would be appreciated.

Cheers

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11 Replies
admin
Immortal
Immortal

Are any screensavers enabled in the virtual machines?

If so, try disabling them

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MattMeyer
VMware Employee
VMware Employee

Did you install the VMTools? This sure seems really odd.

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Aloosh
Contributor
Contributor

Hi Guys/Gals

I have gone through and disabled all the Screensavers on the VM's but that did not help. I still cant figure out why the CPU graphs are so high. What makes it more strange is the fact that when you click on the alarms tab for the ESX Hosts all the indicators are Green.

Oh yeah and all VMs have VMWare tools installed and also this problem only started to happen a few weeks after the environment was built. VC is connecting to a SQL 2000 back end if that helps.

Message was edited by:

Aloosh

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mfleener
Contributor
Contributor

Make sure you have upgraded the virtual hardware if you have not already done so. Another tip would be to make sure your VMs are only using one proc each, this tip alone normalized my data center and actually speed up VMs for us. Its counter intuitive but running with single procs, you won't have to wait in the que until the second proc is available.

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dgrace
Enthusiast
Enthusiast

See here:

http://www.vmware.com/community/thread.jspa?messageID=517710&#517710

(Valid for whatever version of Windows...)

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Aloosh
Contributor
Contributor

Thanks dgrace,

I saw that post but thought it was for NT4 systems only. I will read it properly and check my VM's. Hopefully this will fix my little problem.

Cheers,

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Aloosh
Contributor
Contributor

I went through and compared all of the config files with similar physical dual CPU machines and all the settings seem to be the same. The VM's indicate they are ACPI Multi proc machines and all seems to be ok. I am sure the VM's were built as dual CPU machines from the start. I dont understand what the exact issue is but I dont think it is the single/dual proc issue outlined above Smiley Sad

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admin
Immortal
Immortal

In the performance graphs, what is the cpu usage of the individual VCPUs and what is the total usage ?

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Aloosh
Contributor
Contributor

Well in each of the VM's the CPU graphs are on or near zero % utilization whereas on the ESX serves one of them sit around the 95% mark while the other one sits near the 75% mark. That is because one of the VM's has a CPU utilization of 0% as well and is identical to all other VM servers.

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dsmedtp
Contributor
Contributor

I had some problems when i first looked at these graphs.

Until i went to find out the exact meaning.(i think, someone correct me if i'm wrong)

Seems that the CPU% graph represents CPU usage in percentage over the collected interval. So it can well be that within the interval of the stats, CPU has never been higher than the current level, and therefore you are now at 100% (or thereabout).

Take a look at the Absolute value in MHz, and see if that is closer to the real picture.

I'm having a similar issue with a VM and the performance graphs: somehow an application on the VM always takes up 100% CPU (task manager in the VM), no matter what i set the maximum CPU resources to.

So i have set the CPU limit to 1GHz, but since it used to be 3GHz, it always show a 33% CPU usage in VCenter, even though in reality it is using 100% of its presently allocated resources.

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masaki
Virtuoso
Virtuoso

There are several threads on different cpu graphs with windows multiprocessor guests.

Here is one:

http://www.vmware.com/community/thread.jspa?messageID=514593&#514593

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