[ntp:questions] Time steping regardless of "-x" slew only option

David Woolley david at ex.djwhome.demon.co.uk.invalid
Sat Jun 23 14:04:05 UTC 2007

In article <1182604153.521076.24710 at m36g2000hse.googlegroups.com>,
vwvr6vw <brian.l.hostetler at lmco.com> wrote:

> I am using the xntpd daemon with the AIX OS.  From what I have read,

You are either using an extremely obsolete version, or it is misnamed.
In either case, either install a correctly named modern version, or seek
support from your vendor.  If you want to continue here anyway, please 
indicate the version number (if it is 3 point something, it is obsolete).

> seconds to be slew'ed instead of step'ed.  However, I am seeing steps
> that are less than 3 seconds and show no pattern(anywhere from 0.1
> seconds to 1.7 seconds).  The only thing I can figure is that since

Something is seriously broken.  If the steps are in the same direction,
you are losing interrupts or your static frequency error is outside the
limits that ntpd can correct.  If the steps average to zero, you have a
seriously congested network or you are using servers that are too far
from you.  In the former case, either traffic shape at both ends to give
ntp priority or investiage the huff and puff option in current versions.

> ntp is selecting a different server to sync to, it does not follow the
> slew only logic that should be applied by the use of the "-x" option?

Even the obsolete version synchronises to a weighted mean of the candidate
servers.  If your servers are not within about 10ms of true time, remove
them from the configuration.

> i.e. if I only had one server defined in my config file and it
> stepped, I would not have a problem, but if I have two servers that
> are out of sync, then I could see a steps on my processor as it ping
> pongs back and forth between the two.

You should have four (possibly three) so that if one server is out of
sync it will be detected and excluded from being used.

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