[Solved] VM Times Are Wrong

Discussions about using Windows guests in VirtualBox.
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foobunny
Posts: 7
Joined: 12. Oct 2021, 15:38

[Solved] VM Times Are Wrong

Post by foobunny »

I have Virtualbox and the guest additions installed on a Windows 10 host. I've created two Windows Server 2019 guest VMs. One VM is a domain controller and the other is a member server. The host system and the VMs have been running since I created them three days ago. However, the times on the two guests are very far out of sync to the point where they are not working correctly. The domain controller thinks it is two days ago, the member server thinks it is one day ago. Why are the times so far out of sync if the host and guests have been online the whole time? How can I fix it so my guest VMs don't get destroyed by bad time sync?

I've verified the host time is correct. I've verified the guest systems' Windows Time service is running. I've verified network connectivity between the guest VMs and between the VMs and the host.

Edit: Rebooting the guest VMs via the Virtualbox console did cause the time to sync with the host. However, rebooting the guest VM from within the guest OS did not cause a time sync. These are server systems which are intended to be online all the time, so this is not a feasible method to resolve the issue.
scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: VM Times Are Wrong

Post by scottgus1 »

Install Guest additions in each VM. This might enable time synch. (just a guess so far)

Also, for each VM, Start the VM from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the VM from within the VM's OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip it, and post the zip file, using the forum's Upload Attachment tab.
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: VM Times Are Wrong

Post by mpack »

All PCs will drift with time, VMs more so since time is shared with the host. Mostly it isn't a problem if the PC has access to a network time server. Is that not the case here?

And yes, installing the GAs can improve time sync. ISTR that the paravirtualization API might have an effect too.
foobunny
Posts: 7
Joined: 12. Oct 2021, 15:38

Re: VM Times Are Wrong

Post by foobunny »

The host system does get it's time from the internet. I'll work on getting those logs.
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: VM Times Are Wrong

Post by mpack »

foobunny wrote:The host system does get it's time from the internet. I'll work on getting those logs.
I asked about the guests. I presume the host isn't losing time sync.
foobunny
Posts: 7
Joined: 12. Oct 2021, 15:38

Re: VM Times Are Wrong

Post by foobunny »

Thank you all for the help. It is working correctly now. I didn't realize the Guest Extensions had to be installed in the guests as well as on the host. I installed the Guest Extensions in the guests and the VMs appear to be keeping time now.
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: VM Times Are Wrong

Post by mpack »

foobunny wrote:I didn't realize the Guest Extensions had to be installed in the guests as well as on the host.
They don't. Guest Additions (clue is in the name!) are added to Guests only. This consists of a driver pack for supported guests that allows it to work better as a VM, with better graphics, shared folders without needing a network, better time sync, clipboard copy, drag and drop etc.

There is an Extension Pack plugin to extend the host software capabilities (e.g. adding USB2/USB3 support), but that has nothing to do with this discussion.

Anyway, thanks for reporting back. Marking topic as Solved.
foobunny
Posts: 7
Joined: 12. Oct 2021, 15:38

Re: VM Times Are Wrong

Post by foobunny »

Thank you for correcting my terminology. I learn something new every day.
Last edited by mpack on 20. Oct 2021, 12:38, edited 3 times in total.
Reason: Remove unwanted verbatim quote of immediately preceding post.
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