CPU Sockets vs. Cores

Paul Riker asked:

We are looking at software that is licensed by socket. Right now our hypervisor (EXSi) underutilizes the 2 socket 8 core processing power it has. Most guests only have 4 virtual cores. In order be compliant with the software I can either a) buy 2 cpus licenses b) buy a dedicated server or c) pull one of the sockets from the hypervisor. C is a non-cash move. My question is, which performs better a vm using 8 virtual cores from 1 socket or 2 sockets?

I should mention that the application is Oracle 11 DB Standard Edition.

My answer:


Since your multiple core server is bsed on NUMA architecture, you’ll generally get better performance when the VM is using 8 cores from 1 CPU, instead of 4 cores from each of both CPUs. VMware will do the right thing most of the time.

To understand this issue in more depth, you’ll definitely want to read VMware’s NUMA documentation.

Whether you need to physically remove a CPU to make Oracle happy is a licensing issue, rather than a technical issue, and is not something we can help you with.


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