[ntp:questions] time to sync vs ptp?

matthew.garman at gmail.com matthew.garman at gmail.com
Thu May 30 18:41:27 UTC 2013


I have a server running NTP 4.2.2 (as part of the RedHat 5.7 release).  Last night I changed it's /etc/ntp.conf file, specifically the "server xyz" line to point to a new NTP server.

After doing this, the clock's offset was *increasing* after an hour.  Offset is measured by "ntpdate -q peer".

>From what I've gathered about NTP, it attempts to adjust clocks "gently" and "slowly".  What I'm doing now, and I'm sure this will make some cringe, is to run "ntpdate -u -b peer" in a loop, sleeping two seconds between runs.  I understand this is the opposite of slowly and gently.

But is there a way to somehow combine the behavior of both?  Be a little more aggressive like ntpdate, but retain some of the "politeness" of the daemon?

For what it's worth, I've recently been playing with the open-source PTPv2 daemon.  It appears to "beat the system clock into submission" rather quickly---I see syncs occurring typically in a matter of minutes.  Is there a way to make NTP act more like PTP with regards to getting clocks sync'ed quickly?

I know I'm using very figurative/non-specific terminology here... but I'm trying to wade through all the NTP documentation, but it quickly gets over my head, and I'm not sure what's applicable and what's not.  Hopefully this list can help me get a better handle on this stuff.

Thanks,
Matt



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