On 06.04.15 08:00, Alon Bar-Lev wrote:
>
>
> ----- Original Message -----
> > From: "Shahar Havivi" <shah...@redhat.com>
> > To: "Alon Bar-Lev" <alo...@redhat.com>
> > Cc: vdsm-devel@lists.fedorahosted.org
> > Sent: Monday, April 6, 2015 2:54:07 PM
> > Subject: Re: [vdsm] vdsm hosts clock sync
> >
> > On 06.04.15 07:50, Alon Bar-Lev wrote:
> > >
> > >
> > > ----- Original Message -----
> > > > From: "Shahar Havivi" <shah...@redhat.com>
> > > > To: vdsm-devel@lists.fedorahosted.org
> > > > Sent: Monday, April 6, 2015 2:44:06 PM
> > > > Subject: [vdsm] vdsm hosts clock sync
> > > >
> > > > Hi,
> > > >
> > > > I want to add a new feature that reports migration actual downtime (the
> > > > time
> > > > that the VM was inaccessible to the user).
> > > >
> > > > Libvirt reports that information but the vdsm hosts need to be in sync
> > > > by
> > > > clock
> > > > time.
> > > > I can measure the ping for NTP server an report back to the user if the
> > > > ping
> > > > is too long (more then ~100ms or so) - a way to do that is via ntpstat
> > > > shell
> > > > command.
> > > > The NTP delay can be report back via vdsStats and can be performed every
> > > > few hours or so.
> > > >
> > > > Anyone knows of a better way that we can sync between hosts?
> > >
> > > I am unsure how a ping to clock source is helping, can you please explain
> > > more?
> > In this case I can only report back to the user that its hosts clock is
> > delayed and need to be set...
> > >
> > > If you assume clocks are synced why anything more is needed?
> > Why do I assume that?
> > >
> > > Or would you like to have a solution in which you do not require clock
> > > sync?
> >
> > I do need the clock to be in sync - if not libvirts "actual downtime
> > migration" will be not accurate.
>
> you do not need clock to sync, you need to know the delta between hosts.
>
> but if you assume clock are in sync so what is the actual question?
As I understand from your answer is by having configured ntp the hosts clock
are in sync.
>
> >
> > >
> > > >
> > > > Thank you,
> > > > Shahar Havivi.
> > > > _______________________________________________
> > > > vdsm-devel mailing list
> > > > vdsm-devel@lists.fedorahosted.org
> > > > https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel
> > > >
> >
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