[ntp:questions] Re: time reset, syncronisation lost and Large PPM values

Tom Smith smith at cag.zko.hp.com
Fri Oct 21 18:46:13 UTC 2005


tor wrote:
> Something bothers  ntpd so it looses sync about every half hour.
> The messages from two versions of ntpd are given below.

This is your problem:

> Oct 19 17:19:09 srv3 ntpd[19356]: frequency initialized 500.000 from
> /var/lib/ntp/drift

> Oct 20 15:37:13 srv3 ntpd[20655]: frequency initialized 500.000 PPM from
> /var/lib/ntp/drift

> Oct 20 15:54:28 srv3 ntpd[20655]: frequency error 502 PPM exceeds tolerance
> 500 PPM

> Oct 20 16:09:31 srv3 ntpd[20655]: frequency error 502 PPM exceeds tolerance
> 500 PPM

> Oct 20 16:13:47 srv3 ntpd[20655]: frequency error 502 PPM exceeds tolerance
> 500 PPM
> Oct 20 16:14:51 srv3 ntpd[20655]: frequency error 502 PPM exceeds tolerance
> 500 PPM
> Oct 20 16:15:57 srv3 ntpd[20655]: frequency error 502 PPM exceeds tolerance
> 500 PPM
> Oct 20 16:17:01 srv3 ntpd[20655]: frequency error 502 PPM exceeds tolerance
> 500 PPM
> Oct 20 16:18:06 srv3 ntpd[20655]: frequency error 502 PPM exceeds tolerance
> 500 PPM

You have acquired and institutionalized an absurd frequency correction
(drift rate). This may have happened because the time was not set
before starting ntpd, because the server stepped after ntpd was started,
because you are running ntpd with the "-x" option, because ntpd
was shut down or the system rebooted while ntpd was in the middle of
slew correction, or a combination of these.

You need to check your configuration and re-initialize things.

1) Make sure you are NOT using "-x" in the ntpd command line
2) In /etc/step-tickers, enter a list of reliable NTP servers that are
    likely to be up at the time your system boots
3) Make sure that all of the servers in /etc/ntp.conf are good and
    reporting similar times
4) # service ntpd stop
5) # rm /var/lib/ntp/drift
6) # service ntpd start
7) Wait for a day or 2 for things to stabilize without shutting down
    ntpd or rebooting the system

-Tom




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