There have been several issues with VM timekeeping in the past but according to the latest documents that I've read (KB1006427 and http://www.vmware.com/pdf/Perf_Best_Practices_vSphere4.0.pdf) this shouldn't be much of a problem today. Would anyone vote against running NTP stratum 2 and stratum 3 servers on SLES 11 64bit VMs on ESX 4.0 or later?
Thanks in advance for any input regarding this topic!