vCPUs, sockets vs cores, which one to use, when?
Posted on 2012-03-15
Been trying to figure out how to select virtual CPUs for my VM's on an ESXi 5.0 host and am looking for practical advice for a lightweight "home lab" environment, with 3-4 always running VM's and another 2-4 VM's running during weekend "lab time". (Over time the numbers may well increase, of course.)
Am running all Windows OSes at this point, like Win 7 (32 and 64bit), WHS2011, Windows Server 2008, etc. but plan to start adding a few linux VMs in the near future.
I have an Intel i7 (quad core) processor. Depending on the OS, I can select 1 - 8 sockets and 1 - 8 cores in combinations not exceeding a total of 8.
I have 3 questions:
1. Will Windows 7 and WHS 2001 actually make use of multiple CPUs out of the box for standard "user" workloads, e.g. web browsing, editing, including photos, video streaming, etc, or do I need to do some config work to make it work? (just need to know if more work is needed, not the actual work at this point - I can look that up later)
2. If I just want to give a VM 2 vCPU's, should I pick 2 sockets and 1 core over 1 socket and 2 cores or vice versa?
3. With hyperthreading enable do I need to give an extra core for each socket, (or socket for each core??) or does it work regardless of cores/sockets assigned, i.e. will it work with 1 vCPU (1 core on 1 socket)?