[ntp:questions] Can a clock drift be too big for ntpd?

Patrick Nolan pln at glast2.Stanford.EDU
Thu Oct 25 17:12:59 UTC 2007


On 2007-10-25, Spoon <root at localhost> wrote:
> Patrick Nolan wrote:
>> Patrick Nolan wrote:
>>> Patrick Nolan wrote:
>>>> I realized something since yesterday.  This machine's unique feature is that I
>>>> compiled a new kernel to add the Reiser file system.  I downloaded the
>>>> source RPM for the exact version that came with the distro, and the only
>>>> thing I changed was to enable ReiserFS.
>>> I got a chance to reboot the machine with the original distro kernel,
>>> without Reiser FS.  The clock problem goes away.  ntpd syncs up and stays
>>> synced.
>>>
>>> My next step will be to make a kernel with Reiser but with HZ reduced from
>>> 1000 to 250.  Stay tuned for further developments.
>>>
>>> This is kernel 2.6.18 running on an Intel Core Duo, 2.4 GHz.
>> 
>> It works.  With kernel HZ reduced to 250 and a Reiser disk mounted,
>> ntp is able to sync.  I have gone back to a conventional ntp.conf with
>> multiple servers.
>
> If I understand correctly, the problem was HZ=1000?

It was the combination of Reiser FS and HZ=1000.  
HZ=250 with Reiser works.
HZ=1000 without Reiser works.
HZ=1000 with Reiser doesn't work.




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