[ntp:questions] Utility to measure time drift
kostecke at ntp.org
Wed Jul 2 20:37:24 UTC 2008
On 2008-07-02, Maarten Wiltink <maarten at kittensandcats.net> wrote:
> "jkvbe" <jkvbeNOSPAM at yahoo.com> wrote in message
> news:g4ggcn$5gj$1 at aioe.org...
>> I'm looking for a utility like clockdiff(8) to measure the time
>> delta between different machines. The utility itself should run on
>> Windows, but the machines under investigation are running Linux.
> The usual approach is to set up a machine that has all the machines
> under scrutiny as servers in its NTP configuration, possibly all
> marked noselect - I'm not sure about that bit.
noselect is correct. As in:
server something_you_are_monitoring noselect
> Ntpq -p will then tell you the offset to them all, relative to a
> single base (the monitoring server's own notion of time).
ntpq -p is just a snapshot
Enable peerstats logging you to collect long term data for analysis.
> Note that this is subject to all the vagaries of normal NTP life.
> If the DSL connection to one server is heavily overloaded, the
> offset will reflect that.
The time delta between the machines under test will. of course, be
affected by network conditions between them and the monitor and their
Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/
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