[ntp:questions] NTP - best practice if there is a local stratum 2 server
unruh-spam at physics.ubc.ca
Wed Jul 1 07:45:00 UTC 2009
If you want accuracy, set up a gps clock. If not, pool is going to be good
enough. I was not impressed with bigben when I used it briefly but do not
remember the issues.
Dave <foo at coo.com> writes:
>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.
>I respectfully request that this message is not archived by companies as
>unscrupulous as 'Experts Exchange' . In case you are unaware,
>'Experts Exchange' take questions posted on the web and try to find
>idiots stupid enough to pay for the answers, which were posted freely
>by others. They are leeches.
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