s1xth
VMware Employee
VMware Employee

Opinions: Enable Time Sync in Vmware Tools between ESX Server and Guest VM?

Hey guys....I just wanted to know what you guys though about enabling Time Sync in Vmware Tools on Guests to sync with the ESX server? Do you guys enable that feature or leave it disabled? I have just been letting my VM's get their time information from the DC like always, but in the future I am going to be adding a domain controller (secondary or third DC) in the mix as a VM and I was told that you need to have at least the DC sync with the NTP service on the ESX server...just wondering what everyone has been doing for time syncing...or what the 'proper' method is for the guest vm's....

thanks!!

http://www.virtualizationimpact.com http://www.handsonvirtualization.com Twitter: @jfranconi
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5 Replies
Formatter
Enthusiast
Enthusiast

I usethe time server on esxi in the configuration, then let all the VM's set the time from the server, seems to work fine.

9 VM's, 1 Web server 2003, Server 2003 r2 DC, 4 XP Pro and some experimental machines.

LarsLiljeroth
Expert
Expert

Hi

We do not use the Vmtools timesync in the VM. We use the AD as our main time source and the AD uses i Nist time source.

One of the reasons for this is that we do not want to rely on the tools to do this sync. If Vmtools fails on a DC then we get time skew.

But i think the main thing is that you do not mix it.

But this is one of the this that have been discussed alot on the forum so take a look here and maybe search more... >

http://communities.vmware.com/docs/DOC-5961

http://communities.vmware.com/message/906301#906301

http://communities.vmware.com/docs/DOC-6040


Best regards

Lars Liljeroth

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s1xth
VMware Employee
VMware Employee

Lars...

Thanks for the great answer..I have read everything and understand. I have one more question though, as it wasnt mentioned, should I be enabling NTP Server in ESX if all the VM's are syncing to the PDC? I noticed that my ESX servers sometimes fall behind on keeping time correctly, but it has not effected the running vm's (as it shouldnt becuase I do not have the vm's set to sync to the ESX server).

Thanks

http://www.virtualizationimpact.com http://www.handsonvirtualization.com Twitter: @jfranconi
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williambishop
Expert
Expert

You should use NTP to time source, and it is acceptable to use tools to sync time (several thousands of vm's doing just that). Also, on your template select it to check vmtools version on boot and update automatically.

Have your ESX hosts time sync, have the guests sync to the host....If you have issues with esx keeping time, you have configuration issues that you need to look at.

If you have a server that requires isolated time, then separate it out to NTP by itself (domain controllers, etc) by all means, but it is a valid means of time control to use tools.....

Ita feri ut se mori sentiat
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LarsLiljeroth
Expert
Expert

Hi

Yes you should do that to make sure that time on the ESX is in sync. If you have to go through logs you want them to be correct.


Best regards

Lars Liljeroth

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