Messages in this thread | | | Subject | Re: The ext3 way of journalling | From | Bernd Petrovitsch <> | Date | Mon, 14 Jan 2008 10:57:09 +0100 |
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On Mon, 2008-01-14 at 09:48 +0000, Tuomo Valkonen wrote: > On 2008-01-14, Bernd Petrovitsch <bernd@firmix.at> wrote: > > Yes, that is a usual bug/problem in common distributions[0] as there is > > no real guarantee that your clock is not far off. > > It isn't, right after boot. But while the system is on, it sometimes > starts advancing very fast, 15min a day or so. To my knowledge, the > time the CMOS clock is not used then, but rather the kernel tracks the
ACK.
> time based on scheduler interrupts, with ntpd occasionally correcting. > However, ntpd refuses to correct when the time has drifted too much, > causing even further drift.
That shouldn't happen.
> > That the reason to activate `ntpdate` unconditionally: It sets the > > current time to an (somewhat) accurate value and `ntpd` handles the > > rest. > > Nope, as explained above. ntpdate at boot wouldn't help much, because > the time is (approximately) correct after boot. It only drifts after it.
Aha. That's also strange. `ntpd` is able to (and always does AFAIK) modify the speed of the clock (to keep it synchronized) so that the error is usually much smaller than 1 second - also if you are behind high-jitter links and/or an a high stratum. That leads to the question why the clock starts to run like crazy at some time so that `ntpd` can't cope with it. Playing with `ntpd` parameters (e.g. increasing ) doesn't help I assume.
Bernd -- Firmix Software GmbH http://www.firmix.at/ mobil: +43 664 4416156 fax: +43 1 7890849-55 Embedded Linux Development and Services
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