[ntp:questions] Quick sync between two computers not connected to the internet

David Lord snews at lordynet.org
Mon Mar 22 10:24:27 UTC 2010


pc wrote:
> Has anybody noticed the first word in cnoyes2's subject line:
> "Quick" ?
> NTP can take hours to settle, and is better suited to configurations
> where
> the computers run 24*7.
> 
> How quickly do you need to achieve sync? How often are the PCs
> switched off
> and cold-started?

For me using "iburst" for server line and "ntpd -q" before
starting ntpd will get within 10ms or so. With just two servers
I'd expect one having to be chosen as in some way better and have
the second synchronise to that before starting ntpd. Here using
"ntpd -q" twice, prior to starting ntpd, seems to always get
within a couple of ms. Assuming a good and low drift value it
will converge from that point. I've occasionally seen problems
with just two systems both set as peers when drifts are in
opposing direction when I've seen a large divergence before
settling down so I'd avoid that configuration (possibly more
recent ntpd is better).


David




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