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keany
Contributor
Contributor

CPU at 100%

Hello,

I noticed that one of our Virtual Server hosting Terminal Services Folders for XenApp is running at 100% cpu. I am reluctant to increase the number of cores per socket from 1 to 2 to improve performance as increasing the number of Virtual CPU's after the OS install will "RENDER IT UNSTABLE"; ACCORDING TO THE WARNING. My Question is does Virtual CPU's (in the warning)refers to the number of VIRTUAL SOCKETS or the NUMBERS OF CORES PER SOCKETS?  And also any suggestion on how to increase safely.

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Thanks Ahead for any help.

Cheers

Keany

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6 Replies
homerzzz
Hot Shot
Hot Shot

The number of virtual CPUs is the number of virtual sockets multiplied by the number of cores per socket.

What is the OS in question. I have not run into issues moving from 1 vCPU to 2 vCPUs on any modern OS. Just shut down the VM, add a virtual socket or core, then power the VM on.

Older Windows OS's you had to change the HAL when going from MP to SP.

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keany
Contributor
Contributor

homerzzz!

thanks for the reply, I am fairly new at this, could you please tell me if for example, number of virtual sockets =2 refers to the 2nd CPU installed on the server ????

I appreciate your help.

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rachelsg
Enthusiast
Enthusiast

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homerzzz
Hot Shot
Hot Shot

At the virtual level (forget physical CPU for now), a virtual sockets =2 means the virtual machine OS will see its CPU resources as 2 seperate CPU sockets. If you have 1 virtual socket and 2 virtual cores per socket configured for the VM, the OS inside the VM will see its CPU resources as 1 dual core CPU.

In either case, there is no difference in the amount CPU resources that are assigned to the VM. 2 virtual 1 core sockets is the same as 1 virtual 2 core socket.

Within the guest though, it makes a difference if products running inside the guest are licensed per CPU socket vs. CPU core. Certain OS editions will also see the CPUs allocated differently depending on the vitual CPU configuration.

Hope this helps.

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ReinerHeinz
Contributor
Contributor

I had a similar issue but it was caused by a hard set memory limit in the options tab.  IE the vm had a limit of 4gb set, but the memory had been over provisioned to 8gb so it was swapping out 4gb to disk.  Really eats up the cpu and ruins the performance!

Hope you find your issue.

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King_Robert
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Hot Shot

Also check vmware tool running or not..?

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