[RndTbl] strange NTP problem on one of 3 peers
john at johnlange.ca
Thu Apr 26 08:40:38 CDT 2012
Just to confirm an earlier point, ntp will stop trying to sync the
clock if it gets too far out.
This was a very common problem on VMs and a lot of people resorted to
running ntpdate (or more recently ntpd -q which is much "gentler") on
a cron at frequent intervals just to keep it close. (I haven't noticed
this happening so much recently so this must be a problem that has
In your case you say your not virtualized... wait.. woah.. You're not
There are settings for ntp which tell it never to give up no matter
how bad the clock skews.
Take a look at the ntp man page ( http://linux.die.net/man/8/ntpd )
and search for the word "panic". Then read the sections "POLL INTERVAL
CONTROL", and "THE HUFF-N'-PUFF FILTER".
Then read this: http://www.eecis.udel.edu/~mills/ntp/html/miscopt.html#tinker
Specifically, you put "tinker panic 0" in the config file.
Also, if your bios clock is way out, look at starting ntp with the
"-g" option (but this only applies at startup).
And finally, run ntpd in debug mode ( -d ) and watch it in real time
on the console.
ntp wins my award for the software that seemingly does the most simple
task but is in fact doing something massively complex.
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