[ntp:questions] 4.2.4p8 -> 4.2.6p5 less frequent driftfile updates?

Terje Mathisen terje.mathisen at tmsw.no
Thu Dec 19 15:54:04 UTC 2013


Jochen Bern wrote:
> Hello everyone,
>
> about 40h ago, I updated half a platform from CentOS 6.4 to 6.5, which
> includes updating ntpd from ntp-4.2.4p8-3.el6.centos.x86_64 to
> ntp-4.2.6p5-1.el6.centos.x86_64. One of the updated machines holds the
> platform's Internet-bound NTP connections, and has some extra monitoring
> for that - which now alerts us to the fact that by now, the driftfile
> gets updated only every 6+ hours, rather than every hour (modulo sync
> problems) as before.
>
> A quick scan seems to confirm that the update frequency is tied to the
> ntpd version running on the machines:

This is intentional, in order to lace less load on the hard drive/flash 
drive of embedded/small servers. :-)

The update is written only if the delta in time or frequency is large 
enough afair.

Terje
>
>> $ date ; for MACHINE in $INTERNETFACING ; do echo "" ; ssh $MACHINE \
>>> "rpm -q ntp ; ls -l /var/lib/ntp/drift" 2>/dev/null ; done
>> Mi 18. Dez 19:03:06 CET 2013
>>
>> ntp-4.2.6p5-1.el6.centos.x86_64
>> -rw-r--r--. 1 ntp ntp 7 18. Dez 15:18 /var/lib/ntp/drift
>>
>> ntp-4.2.6p5-1.el6.centos.x86_64
>> -rw-r--r--. 1 ntp ntp 7 18. Dez 18:20 /var/lib/ntp/drift
>>
>> ntp-4.2.4p8-3.el6.centos.x86_64
>> -rw-r--r--. 1 ntp ntp 7 18. Dez 18:11 /var/lib/ntp/drift
>>
>> ntp-4.2.4p8-3.el6.centos.x86_64
>> -rw-r--r--. 1 ntp ntp 7 18. Dez 18:29 /var/lib/ntp/drift
>>
>> ntp-4.2.4p8-3.el6.centos.x86_64
>> -rw-r--r--. 1 ntp ntp 7 18. Dez 18:21 /var/lib/ntp/drift
>>
>> ntp-4.2.6p5-1.el6.centos.x86_64
>> -rw-r--r--. 1 ntp ntp 7 18. Dez 14:13 /var/lib/ntp/drift
>>
>> ntp-4.2.6p5-1.el6.centos.x86_64
>> -rw-r--r--. 1 ntp ntp 7 18. Dez 13:22 /var/lib/ntp/drift
>
> Is this change of behavior intentional?
>
> Kind regards,
> 								J. Bern
>


-- 
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"



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