Re: [Xen-users] Clock problems on Squeeze/Xen4 (clock jumps 50 minutes ahead)

[Aleix Dorca Josa <adorca@xxxxxx>]

Yeah, that's what I first thought too... but it happens at random on different 
machines, all using the same kernel/xen combinations but it is also true that 
all are using the same hardware (PowerEdge 1950III). Using xen3 I also had 
problems with the 'Time went backwards' issues but changing the clocksource to 
jiffies solved everything.

It is also true that I had not seen the issue in Xen4 for a long time since 
using ntpdate it corrected itself without affecting services. It wasn't until I 
started using Dovecot and ntp that I had real problems.

Tomorrow I'll install Ubuntu 12.04.1 LTS on a server and move some DomU's 
there. We'll see how it works. Changing the hardware now is not possible I'm 
afraid.

I could also try to update firmware's and stuff on the PowerEdge, anyone done 
this?

Thanks for your comment Carlos,

Aleix.

El 27/08/2012, a les 18:16, Carlos Ribas <carlos@xxxxxxx> va escriure:

> My Dom0 is Debian Squeeze with "xen-linux-system-2.6.32-5-xen-amd64" and 
> DomU's are Squeeze too and I don't see the problem you said in my environment.
> 
> To me this look like hardware problem. 
> 
> Regards,
> 
> -------------------------------
> Carlos Eduardo Ribas
> 
> 2012/8/27 Aleix Dorca Josa <adorca@xxxxxx>
> Nope, all is 64 bits (Dom0 and DomU's).
> 
> Aleix.
> 
> El 27/08/2012, a las 16:05, Steven Timm escribió:
> 
> > Are you running 32-bit domU's or 64-bit? I have seen the problem many times 
> > under xen 3.1.2 but only with 32-bit guests on 64-bit hosts.
> >
> > Steve timm
> >
> >
> >
> > On Mon, 27 Aug 2012, Aleix Dorca Josa wrote:
> >
> >> Hi all,
> >>
> >> My xen farm is plagued with this 'Jump 50 minutes ahead' problem. All my 
> >> machines run Debian Squeeze and Xen 4 in Dom0. DomU's are Squeeze too. I 
> >> thought this was a hardware problem but then I saw this (kind of old) 
> >> messages:
> >>
> >> http://lists.xen.org/archives/html/xen-users/2011-02/msg00609.html
> >> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=599161
> >>
> >> After reading all available info I still don't know if the bug has been 
> >> resolved in later builds of either the kernel or xen on Squeeze. Has 
> >> anyone got new information on this?
> >>
> >> I see that the clocksource=pit on the grub command line does not seem to 
> >> fix the problem. Any other hints? Change to Ubuntu server? Build my own 
> >> xen binary? Use Debian's backports to change the kernel version?
> >>
> >> This is kind of a big problem for me since the error kills ntpd on DomU's 
> >> and then Dovecot's processes stop themselves when time is corrected. 
> >> Scripts to workaround this are fine but I would rather much prefer for the 
> >> clock not to jump ahead.
> >>
> >> Thanks a lot,
> >>
> >> Aleix.
> >> _______________________________________________
> >> Xen-users mailing list
> >> Xen-users@xxxxxxxxxxxxx
> >> http://lists.xen.org/xen-users
> >>
> >
> > ------------------------------------------------------------------
> > Steven C. Timm, Ph.D  (630) 840-8525
> > timm@xxxxxxxx  http://home.fnal.gov/~timm/
> > Fermilab Computing Division, Scientific Computing Facilities,
> > Grid Facilities Department, FermiGrid Services Group, Group Leader.
> > Lead of FermiCloud project.
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxx
> http://lists.xen.org/xen-users
> 


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