virtualbox.org

Hy all,

I've got a couple of machines up an running.
I just started with them and noticed on quite some machines (running on the same host), that during one single week the clock gets screwed by a hour and a half (approx).

I've got ntp running since I've noticed it and everything is fine.

My question is rather whether this is normal / to be expected, or might it hint to some problem wither in my setup or (hope not) host hardware which transpires to the virtual boxes?

As I said, there is no problem whatsoever atm due to the ntp-daemon. But has anyone else experienced this? Is this normal, or should I be concerned / check the host hw?

Thanks!

It is normal for any PC time to drift if it doesn't have access to the internet, or is not manually corrected. VMs more so I would expect, especially if you never shut them down.

mpack wrote:It is normal for any PC time to drift if it doesn't have access to the internet, or is not manually corrected. VMs more so I would expect, especially if you never shut them down.

Thank you for your answer.

I do realize that it is normal. However the drift is somewhere up to 10 min from one day to another, if the ntp daemon is not up (obviously).

Yes the machines are up all the time / no down time / restart / shutdown, and they are always connected to the net.
Again, with ntpd - no problem.

It's just that the amount was rather shocking to me. 10 minutes during one day seemed odd / quite a lot. A couple of seconds - sure, maybe a minute if it has to.

I was just wondering if this amount of drift was common / seen, or if it was something I should investigate further rather than rely on ntpd to deal with it.

The guest who has this problem is running FreeBSD - yet I can't imagine that to be the issue. Even the host is drifting yet not nearly as much as the guests.

Thanks again

For a physical PC that drift would be a lot, since it has an actual hardware timer keeping system time to parts per billion each day, in addition to an RTC. A VM has a simulated hardware timer, and shares real time with a host. I've not done any experiments, but it wouldn't surprise me that a VM drifts off quite quickly. I believe one of the jobs done by the GAs is to stop this time from diverging too far, but you haven't mentioned the GAs as far as I can see. AFAIK there are no official (Oracle supplied) GAs for FreeBSD, and I can't tell you what features the unofficial FreeBSD project ones support.