We run our vm's on an older vcenter. 3 hosts, 6 processors, 72 cores, 768 gigs ram, 48 sas drives making around 15 tb of disk space. It is a great feeling to add more ram and disk space (and processors) and be back up in 90 seconds. You can actually add resources HOT (without a restart) if running windows server [top that, you mac people]