[ntp:questions] Utility to measure time drift

Steve Kostecke 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
time sources.

-- 
Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/




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