[uuilly]

I've been using chrony to sync 18 CPUs in a realtime application. I've found it to be a mixed bag. Once it gets syncing, it's really good. I've got it set up so I'm accurate to w/in a few microseconds on my LAN. But getting the initial sync fast is extremely unintuitive, impossible, poorly documented or some combo of all three. I don't think it was designed with the thought that the machines would get rebooted every night -- which is our case. I had to write some upstart scripts to perform the initial sync and then let chrony take over from there...

[mkj]

I've found it needs the following config. Overall far fewer mystery sync issues than the reference ntpd though, nice software.

  initstepslew 300 ntp.server.example.com

[mlichvar]

chrony maintainer here. If the initial sync is slow, it probably means the initial offset of the clock is large and chronyd is correcting it by slewing, which may take a long time. You can use the initstepslew or makestep directive to step the clock on start. A configuration optimized for a fast and tight sync with a local NTP server could be:

  server ntp.lan minpoll 2 maxpoll 4 iburst
  makestep 0.1 1

[uuilly]

Thanks! I'll try it.