[ntp:questions] Stability problem on PowerEdge (SuSE 9.3)
kostecke at ntp.isc.org
Tue Feb 27 00:26:55 UTC 2007
On 2007-02-24, Till Wimmer <news-dfn at substring.ch> wrote:
> Our main server is running SuSE 9.3 on AMD64. I installed the xntp
> package from SuSE (Vers. 4.2.0a-35). Hardware: DELL Power Edge 2850
> uanme -a:
> Linux office 18.104.22.168-21.15-smp #1 SMP Tue Nov 28 13:39:58 UTC 2006 x86_64 x86_64 x86_64 GNU/Linux
> server 127.127.1.0
> fudge 127.127.1.0 stratum 13
You should comment out the LocalCLK until you fix your stability
problem. And then, you should only re-enable the LocalCLK if you
understand why you need it.
> server 0.debian.pool.ntp.org iburst
> server 1.debian.pool.ntp.org iburst
> server 2.debian.pool.ntp.org iburst
> server 3.debian.pool.ntp.org iburst
Some people will tell you that this is a poor choice of servers (e.g.
due to excessive delay). That may be true but it's not germane to your
> disable auth
Disabling auth is not usually a good idea because it can allow someone
with ntpdc to tinker with your ntpd settings remotely. BUT ... this has
nothing to do with your problem.
> Short after starting, everythings looks ok:
> But after 3..5 hours all peers are rejected (ntpq> as) and LOCAL(0) is
> the sync source.
We need to see 'ntpq -p' after your ntpd has been running for those 3-5
hours. We also need to see any ntpd messages in your syslog for that
> Now i found that pps stability is always 512ppm and pll has a huge offset.
You're not using PPS. Look at the PLL frequency, not the PPS stability.
> ntpdc> kern:
> pll offset: 4294.95 s
> pll frequency: 22.694 ppm
The offset is large because your system has been coasting on the
Undisciplined Local Clock and ntpd has not had been able to determine
the right PLL frequency.
> I can't believe that the clock of this server is this terribly
> inaccurate... IMHO it's "professional" hardware. At least it was
> expensive ;)
Price and quality are not always synonymous.
Steve Kostecke <kostecke at ntp.isc.org>
NTP Public Services Project - http://ntp.isc.org/
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