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Aug 16

Windows 2008 Server and VMWare Tools, time sync

If you’re running Windows 2008 Server on a VMWare ESX host with VMWare tools installed, make note that the Windows 2008 Server VM can sync its clock to the ESX host, even if you disable this option in VMWare Tools.

I recently experienced this in an Active Directory environment, and of course the Windows 2008 Server VM was also a domain controller, so it made things stop working for about a half an hour before we could actually pin point what was skewing the clock so badly. Turns out, our ESX host had NTP enabled, but this was syncing the clock 2 hours wrong, and the 2008 Server VM automatically set its clock to this on each reboot.

Disabling the NTP-service on our ESX host and setting the time manually fixed the issue, but of course this is not a good work around.

Update: check out John’s post in the comments bellow for a fix for this. Thanks John.

5 comments

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  1. pvl

    Did you find a resolution other than turning off ESX ntp?

    1. Frode Henriksen

      I’m afraid I haven’t. Others are also reporting on this problem, you could perhaps check out the technet or vmware-forums.

  2. John

    first disable ntp on ESX host.
    second make sure your 2008 dc is not sync using vmware tool, check on vmware to make sure time sync is not check.
    you still want to edit your 2008 dc’s config.vmx file to make sure not syncing up with esx host in anyway. copy exiting vmx file and keep it in a safe place in case something goes wrong. Now open .vmx fiel with windows wordpad and add these lines
    tools.syncTime = “FALSE”
    time.synchronize.continue = “0″
    time.synchronize.restore = “0″
    time.synchronize.resume.disk = “0″
    time.synchronize.shrink = “0″
    time.synchronize.tools.startup = “0″

    basically, I got this from vmware kb and this will literally stop any kind of time sync from host.

    once you got this you should set your 2008 dc to get time from external ntp server such as pool.ntp.com or something like that. You client will always look at your dc and hence you will get the correct time. Otherwise, you 2008 dc clock with be always out of sync whenever your restart your dc.

    Good luck…

    1. Frode Henriksen

      Thanks alot for the info mate!

  3. David Sellens VCP VCAP, etc

    Hindsight is always better than foresight, but it appears that the response above is wrong. While the understanding of how time works is basically right, the way to correct the problem was to correct the time zone on the ESX host to match the time zone on the DC so that the time picked up from the host was correct. ESX kept time in the local timezone while ESXi keeps time in UTC. The only way that the DC was getting the time wrong was if the timezone on the ESX host was wrong.

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