[ntp:questions] "good enough" ntp configuration

Eric nospam-01 at jensenresearch.com
Mon Jun 11 13:43:38 UTC 2007


On Sat, 9 Jun 2007 19:34:51 GMT, jason at extremeoverclocking.com (Jason Rabel) wrote
for the entire planet to see:
<snip>
>Also when using NTP to set the prefer flag to your GPS source as that would
>probably be the most accurate time and prevent NTP from hopping around
>sources or choosing the wrong one.

I can't agree with that statement.  The PREFER keyword can improve sync and reduce
clock-hopping, but it causes unfortunate side effects when the PREFERed clock has
problems.  

It reduces reliability and redundancy in the entire NTP hierarchy that uses that
server and can lead to all your machines becomming unsynchronized from the One True
Time.  PREFER should be avoided if you are interested in high availability rather
than sub-millisecond accuracy.

- Eric




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