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On a VM running RTC 5.0 LINUX 6.5 What is the recommended number of CPU's?


Drake Brown (3634) | asked Mar 02 '15, 8:14 p.m.
I am trying to determine where performance problems are originating from.  I have a vm with 2 cpu's.  Is that typically sufficient?  I don't see any discussion on the deployment wiki regarding recommended number of cpu's.

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Simon Washbrook (67216) | answered Mar 03 '15, 3:44 a.m.
Hi Drake,
The artilce you are looking for in the deployment wiki is:

Principles of good virtualization
https://jazz.net/wiki/bin/view/Deployment/PrinciplesOfGoodVirtualization

In particular you have to pay attention to what you mean by "CPU" in  virtual environment. Many hypervisors count a "core" as a CPU so your 2 CPUs may only correspond to "1 dual core CPU", which is below the minimum number of 4 cores or 2 dual core CPUs or a single quad core CPU.

The other "gotcha" in a virtual environment is over commitment. Hyper visors allow you assign more CPUs to virtual machines there are physically available. The hypervisor then shares the time on those CPUs amongst the virtual machine. This is fine for batch processing programs but can be catastrophic for transaction tasks such as web servers and application servers like RTC. You need to tell the hypervisor that the CPUs and memory are for the exclusive use of the RTC server only. This is called affinity.

A good starting place to read about if you have enough resources for your sever is:

CLM Sizing Strategy
https://jazz.net/wiki/bin/view/Deployment/CLMSizingStrategy

These documents are a good start.

Good luck with your deployment,
Simon

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