Dell T710 time issue, clock loses time every day
I have a Dell T710 here at work that for some reason will not keep proper time. Its a dual quadcore with 32GB ram and runs Windows 2008 R2. Instead of Having multiple servers we run a few virtual machines under Hyper-V. All of the VM's have "time synchronization" enabled and the VM's clocks keep perfect pace with the host clock.
One of the VM's hosts our shop control software and since it utilizes the system time for time stamping actions, its vital the clock be as accurate as possible. Every day I have issues with the clock being slow. In the morning it is usually 2 or 3 minutes slow or on some days (like today), it was a full 10 minutes slow. If I set the server time using the internet time application, the time sets itself correctly and then the workstations follow through with NTP. It works fine but even toward the end of the day the clock is off yet again by 1 or 2 minutes.
The problem is maddening and I have tried everything I could think of and find on the internet including:
- Trying multiple internet time servers
- Using one of those atomic clock programs to adjust the frequency of updates to twice per day
- Manually tweaking the registry keys
- Ensuring that the VM's derive their time from the host which means that the clock drift is related to the host and not the VM's as every VM has the same time the host displays. (e.g. if the host clock is 7:28, all VM's show 7:28)
- One of the VM's is a domain controller BUT the host is not on the domain. This was done to ensure the host is just that, a host for the rest of the network and not part of it.
NOTHING stops the clock from drifting. From my research it could be linked to the fact that the the server load might have an effect on the time but the load is nothing at all, maybe spikes of 10-50%, its a small company. And for the reference time I simply look at my cell phone.
- Disable host time synchronization.
- Point VMs at an accurate NTP server.
- Profit.
If host synchronization is enabled, all the other changes you do aren't going to make a difference, as the guests are going to try to keep syncing up with the hardware time on the host, which is evidently not keeping good time. Effectively, the host-time-synchronization over rides whatever time changes you're making, so turn it off and save yourself a bunch of headache.
For whatever it's worth, I always disable guest-host time sync (with any hypervisor) and point all my servers at a proper NTP source. In a domain, that's done by pointing one DC at an NTP pool, and the other domain machines at it. If not domain-joined, you may as well punch up a script to point all your machines at the same NTP server or pool.