I was wondering if someone would elaborate on the general rule for assigning CPU cores to a Windows 2003 or 2008 server in VMware ESX or ESXI. I am running a host server with 1 quad core Xeon processor. I found that a Server 2008 R2 VM I had running with SQL 2008 on it was pegging the CPU at 100% quite a bit so I added an additional core to the VM which helped.
Could someone give me their opinion on general guidelines as to how many cores to add considering different server configurations? Is one core sufficient in most cases?