I understand that when you make a multi-core VM, the cpu on that VM can not run until the number of physical cores open match the number of Virtual cores on the CPU (virtual dual core can not operate on 1 physical core must have 2 physical cores). I am un sure of how it works with a ESX host that has 2 physical processors that both have multiple cores. Can a dual core VM use a core from both physical processors to run or must the cores be on the same processor.
For instance, you have 2 quad core processors in a ESX host. 3 cores on the first and second chip are being used. Can the VM use the open cores from the first and the second core to achieve its dual core capabilities?
1) The restriction isn't 100% anymore - ESX does have the ability to relax that co-scheduling issue.
2) It will use cores from diferent CPUs if it needs to. It will prefer cores from the same CPU, but go with cross-CPU cores if it needs to.