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andvm
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1to1 vCPU to physical CPU - yet high VM %RDY

Hi,

Can someone please shed some light and explain why certain VM's when very busy peak at almost 10% RDY even though there is no CPU over provisioning on the host.

I expect the host to provide CPU time to the VM almost instantly when requested in above scenario irrespective of how busy the VM is.

I would like to technically understand why this happens and what measures should be taken please?

Thanks

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sjesse
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The % ready is for the entire vm, are you at one vm, then you want to divide that number by 16 which is small.

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sjesse
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How many cpus are the vms you are referring to?

How big are the hosts?

Whats the biggest vm you have?

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andvm
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16 vCPU VMs

44 Physical CPU

Biggest VM has 16 vCPU

Total vCPU = pCPU

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sjesse
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The % ready is for the entire vm, are you at one vm, then you want to divide that number by 16 which is small.

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andvm
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So always need to divide with number of vCPU and check that lower than 5% ?

Good to know if so as do not think this is normally stated clearly enough unless you can refer me to any documentation

btw am using esxtop and V to check this metric

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sjesse
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Yeah, I asked this a year ago, read some of the links

https://communities.vmware.com/thread/599662

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