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Re: [Xen-users] Xen timekeeping best practices

On Fri, Apr 13, 2012 at 9:26 AM, Lloyd Dizon <thecarrionkind@xxxxxxxxx> wrote:
> On Fri, Apr 13, 2012 at 2:49 PM, Remi Gacogne <rgacogne-xen@xxxxxxxxxxxx>
> wrote:
>> Miles Fidelman wrote:
>>> There's a pretty good discussion on the Debian Xen Wiki, at
>>> http://wiki.debian.org/Xen scroll down or search the page for the section
>>> starting: 'clocksource/0: Time went backwards' - which lists several
>>> workarounds note that some of them no longer work with Xen 4 (I think
>>> xen.independent_wallclock=1 is no longer recognized)
>> I second that. While it was possible to get a pretty accurate time in Xen
>> 3 by using independent_wallclock, I have been unable to do so with Xen 4 so
>> far.
>> We have several Xen 4.0.1 production servers, and even by using NTP in
>> dom0 AND domU we have a recurring problem where the clock goes out of sync
>> for an hour or so. Using NTP in each domU with the "disable kernel" option
>> seems to help a bit, but for some users needing less than a few seconds of
>> time drift it is a real issue.
>> I am currently thinking of downgrading some users to Xen 3 to work around
>> this..
> This is annoying, as I am on the verge of migrating production machines from
> Xen 3 to 4.
> I am currently stuck because of time issues with the test machines I've
> already migrated. In our environnement 200 ms of time drift is unacceptable.
> Has anybody had feedback from Xen development teams? Wondering what will it
> take in order to fix this issue...

Does this help at all:


Todd Deshane

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