VMware Communities: Message List - Time Sync ESX 3.5 u4

Re: Time Sync ESX 3.5 u4

GFFG — Thu, 16 Apr 2009 18:05:52 GMT

Lastly does anyone know if esx uses both in the list all the time or just one until it becomes unavailable?

Re: Time Sync ESX 3.5 u4

lamw — Thu, 16 Apr 2009 17:28:41 GMT

Yes this was a decision from our Windows team that they wanted to sync directly to Windows time source and all Window images were setup to not sync with host. I don't believe we ever had our Window VM(s) sync to the host, it was sort of something that was there for awhile. Hope this helped

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William Lam
VMware vExpert 2009
VMware ESX/ESXi scripts and resources at: http://engineering.ucsb.edu/~duonglt/vmware/
http://twitter.com/lamw

Re: Time Sync ESX 3.5 u4

GFFG — Thu, 16 Apr 2009 17:23:58 GMT

Thanks Troy and Lam,

I would tend to agree with your assement Lam. Lam are you saying that previously you had your vmware tools sync to ESX host, right?

You basically unchecked the Vmwaretools sync option and ensureed W32TIME service was enabled on all VM's?

Thats where I am at right now.

I am going to edit the ESX server's NTP settings for my 5 ESX servers and change it to

1) our local time server for Domain as #1 Choice

2) My #2 choice will be the external time server that our #1 server sync's too.

This way all machines's , all servers and workstations all in some way or another are "ultamitly" getting it's time from MICROSOFT'S EXTERNAL INTERNET FACING TIME SERVER.

Thanks! I think this sounds like a good plan.

That PDF was a good read, wow a lot to think about for sure!

Re: Time Sync ESX 3.5 u4

lamw — Thu, 16 Apr 2009 17:06:38 GMT

At a previous company, the Windows group had a similar question and we did the following:

I'm not sure if it's a best practice to sync your VM(s) to your ESX/ESXi host and then have that sync to your external time source, it may be up for interpretation, though our Windows team felt they wanted to directly sync the VM(s) to our AD/external source since they're all connected to the domain. We disable the sync from VM to host, but we do also sync our NTP Client settings on our ESX hosts to our internal NTP server. The reason for the sync is that we also have our Service Console not only authenticate to admin account locally but we also have it talk to AD so that VI Admins can also login using their AD credentials and we only keep one local admin account for the UNIX/Linux group for administrating the host. As you're probably aware, directory services/AD is very time sensitive and you want to make sure you're not drifting too far apart, else the system won't allow you to logon and we felt that it should not rely on the host for the time in case the host loses it's sync so we have two NTP sources.

Hopefully this helps out

Re: Time Sync ESX 3.5 u4

Troy Clavell — Thu, 16 Apr 2009 17:02:32 GMT

have you seen the Timekeeping in VMware Virtual Machines white paper?

Time Sync ESX 3.5 u4

GFFG — Thu, 16 Apr 2009 16:55:01 GMT

Q: If none of vm's sync with ESX via Vmtools then why does setting up ESX NTP client really matter? alerts etc , scheduled tasks?

Q: We use windows time server that is set to get to sync outside to Microsoft's time server. Windows time service then sync's all machines in domain. My question is in ESX server, given the above statement, would it be beneficial to to use the internal domain time server as the #1 time server in ESX? Also is it advantageous to make the 2nd time server an outside source?