[ntp:questions] NTP - best practice if there is a local stratum 2 server
foo at coo.com
Sun Jun 28 16:19:14 UTC 2009
I'm trying to set up the time on a couple of machines at the University
of Washington and have tried two ways:
1) Sync both to the ntp pool - not very successful, as they kept
differing by enough to cause 'make' to say files were created in the
future by a few ms - no doubt due the NFS exported drives.
2) Set one via ntpd (call is master) from the ntp pool, then the other
local machine (slave) read the time from the master. That appears to
work quite well. They at least agree on the time pretty closely now. The
absolute accuracy might not be as good as possible with a local time
server, but for practical purposes it works well.
Searching around, I found that the university does in fact have their
own strtatum 2 time server - I assume in another department to where the
machines I'm using are located. The server is
I assume, for absolute accuracy (which is not important here, but I'm
intersted), this is going to be better than any attempt to set the time
from the ntp pool. Is that correct?
But setting the time from the local server is also going to be cause a
problem if that server fails for some reason.
Is there any way to make use of a local server if it's working, and then
use the pool if its not?
To be honest, this is all a bit academic, as there is no real practical
need to have an accuracy of better than a minute or two on these
machines. In fact, an hour wrong would not make much difference but it
might irritate a few people.
But it is important the two machine agree with each other, as otherwise
files appear to be created in the future by a few ms, which screws up
the 'make' program some times.
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