Reset of Clock on the ESX vm's

[ArunNukala]

Every now and then I have to reset the clock on the ESX VMs as they

are

suddenly way off the correct time, even though NTP is both running

and

working. What I think is happening is that the ESX host is

interfering

with the virtual hardware clock in the VM and completely screwing

things

up. Could this be when it decides to move to another host? Either

way,

can you do something to stop this happening?

[dnetz]

What OS is running on the VM? Are you synchronizing via vmware tools or an NTP client in the VM?

The recommended way to synchronize VM's is by NTP client in the VM, if this is not possible via vmware tools but never both at the same time. There are also considerations to be taken for the NTP client settings and other OS-specific settings. If you're running Linux in the VM, see this KB: kb.vmware.com/kb/1006427

[subtleobserver]

Hi,

We are seeing the same thing on our ESX servers 3.5. We are running Windows XP & Vista on the VMs.

What is the cause of the reset of the clock?

Thanks.

[dnetz]

Vmware tools can only "catch up" a VM's time to NTP, not slow it down. This seems to be one of the main reasons why Vmware recommends running an NTP client in the VM for most environments. If your Windows VM's are part of an Active Directory, they will all by default synchronize its time with the domain controller running the PDC emulator role in the forest.