Solved

Hyper-V Time Synchronization : guest sbs2011 always ahead a few minutes

Posted on 2013-06-10
5
362 Views
Last Modified: 2014-11-12
Hi everyone,

This subject has been discussed a million times, and I have spent a few hours reading one site after the next and I think a need new eyes to have a look at this at tell me what to do.

On many sites (http://blogs.msdn.com/b/virtual_pc_guy/archive/2010/11/19/time-synchronization-in-hyper-v.aspx seems to be the most "official"), it is recommended to NOT disable the Time Sychronization.

One has to disable in the guest VM, on the domain controller (sbs 2011 in my case), that the sychronization is made with the parent host (which is a hyper-v core, not connected to the internet, not in the domain).

I did so and if I query the ntp source, I have pool.ntp.org, which is correct.

If I force a sync, the time is set accurately, but a few seconds later, it jumps again a few minutes (4 in my case). This case is also mentioned on many site (and on the link above).

Please help, this is really driving me nuts :)
0
Comment
Question by:StephRu
  • 3
5 Comments
 
LVL 18

Expert Comment

by:Peter Hutchison
Comment Utility
Really the PDC should be synced with a valid and reliable time source such as a NTP server on the internet and from no where else. Other VMs should sync with the PDC using it as the source (using type NT5DS for w32time).
0
 
LVL 1

Author Comment

by:StephRu
Comment Utility
That's right and that's what I'm doing.

But the PDC (my sbs2011) is always off 4 minutes. It acts as if I didn't disable the sync with the host. The command that I used is :

reg add HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\VMICTimeProvider /v Enabled /t reg_dword /d 0

And as said, if I query the source, it will indicate pool.ntp.org and if I force a sync, it will be correct.. .but a few seconds later, it will change and jump 4 minutes.
0
 
LVL 13

Expert Comment

by:frankhelk
Comment Utility
Looks like a problem with the W32time service acting as NTP client. From my experience W32time is a constant source of annoyance it it's used that way.

I'd recommend to switch to the "real thing" - disable W32time completely and install a classic NTP service. Easy to install and to configure, and works like a charm. Please see this article for a simple howto and further references.

Be sure that W32time is completely disabled when using a NTP client, because 2 services manipulating the system clock will cause unpredictable ( & wrong) results.
0
 
LVL 1

Accepted Solution

by:
StephRu earned 0 total points
Comment Utility
I have abandoned the possibility to configure my client independently from the host, as best practices tell to do so.

So I just updated my host clock and connected it again to the internet, but I really don't like this option, as I really like the idea that my Hyper-V Core was not connected to the local lan (and to the internet).
0
 
LVL 1

Author Closing Comment

by:StephRu
Comment Utility
I never found how to solve my initial question... so I used another way to fix my problem :(
0

Featured Post

Do You Know the 4 Main Threat Actor Types?

Do you know the main threat actor types? Most attackers fall into one of four categories, each with their own favored tactics, techniques, and procedures.

Join & Write a Comment

You might have come across a situation when you have Exchange 2013 server in two different sites (Production and DR). After adding the Database copy in ECP console it displays Database copy status unknown for the DR exchange server. Issue is strange…
It Is not possible to enable LLDP in vSwitch(at least is not supported by VMware), so in this article we will enable this, and also go trough how to enabled CDP and how to get this information in vSwitches and also in vDS.
To efficiently enable the rotation of USB drives for backups, storage pools need to be created. This way no matter which USB drive is installed, the backups will successfully write without any administrative intervention. Multiple USB devices need t…
This tutorial will show how to configure a single USB drive with a separate folder for each day of the week. This will allow each of the backups to be kept separate preventing the previous day’s backup from being overwritten. The USB drive must be s…

728 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now