Re: [Xen-users] dom0 and domU differs after ntpdate

["Marco Strullato" <marco.strullato@xxxxxxxxx>]

After echo 1 > /proc/sys/xen/independent_wallclock 
and an ntpdate on each server the time is right.

Thanks

Marco

2007/11/6, Nico Kadel-Garcia < nkadel@xxxxxxxxx>:

Marco Strullato wrote:
> I'm sorry, I think I don't well understand what you wrote. could you
> be more clear?
> why you suggest me not to run ntp on domUs? Maybe I don't know how xen
> works with ntp....
>
> Thanks
>
> Marco
All NTP daemons work by manipulating a time offset, an offset between
the clock time reported by the hardware clock and the actual time as
deduced from NTP servers. And they also have a second offset, one that
allows them to retain a record over some period of the amount of drift
that consistently happens and adjust for it. It's described here:

    http://en.wikipedia.org/wiki/Network_Time_Protocol

OK? Now imagine that you're a surveyor doing careful work, and you put
some markers down in a convenient place, and you measure how long things
are, and where they are, and you make a nice map, and you record where
your markers very carefully so you can rely on them.

Now imagine some other surveyor starts taking and using your marker, and
*keeps moving it* when you're not looking. You can never hope to get all
your maps done accurately while this is going on.

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