[ntp:questions] Using both Server and Peer in ntp.conf

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Thu Feb 8 19:43:08 UTC 2007

>How many minutes, hours, or days of "holdover" with reasonably correct 
>time you may get depends on the quality of the local clock, the 
>stability of the temperature, the phase of the moon and the whims of the 

We can at least do a bit of arithmetic.

There are 86400 seconds in a day.  If your clock is off
by 11 ppm, it will drift 1 second per day.

If your machine is in an airconditioned machine room, the
average temperature is probably pretty stable.  I'd guess
a second per week would be conservative.

If your machine is in an environment with poor temperature
regulation, the day to day average temperature is probably
the important consideration.

These are my opinions, not necessarily my employer's.  I hate spam.

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