On Mon, Apr 28, 2008 at 7:14 PM, Unruh <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] (Hal Murray) writes: > > >>Sorry it's actually difficult for me to precise this topic for > >>confidentiality reason of course and also because I'm an intern and thus > >>there for a short period. Hence I don't know exactly why myself. This is > >>just one of the requirement of my project. > > >Keeping a handful of machines synchronized to within 10 microseconds > >might be possible. It won't be easy. It's unlikely to be the cheapest > >overall solution to some problem. > > >I suggest you tell your boss that he has given you a hard to impossible > >problem. You are not likely to get 10 uS by just poking a few magic > >parameters into your ntp.conf. Your target is not a reasonable intern > >project. > > Actually he only wanted 50us from what I recall. And it will depend on the > state of the switches, of the network cards, of the temp cycling of the > system, etc. chrony will quite easily achieve 50us. ntp is more difficult, > a) because it throws away 7/8 of the data (which could of course be > compensated by just querying more often) and b) throwing away the data one > it has once been plugged into the feedback loop. (Ie, the system is > essentially markovian) But even with ntp, I think 50us is possible. > > But all this speculation is a bit pointless. Do the experiment. > And if you really want to do it properly, get a gps or two and hook it up > to the machines to measure the actual deviation from true UTC of various > of > the machines, including the server. Then you can subtract the two ( > machine > -server) offsets to see what the relative accuracy is. > In a situation like this, experiment is always better than theory. > (Note, I am a theoretical physicists) > > I agree with you on this point. The theory here doesn't seem to be of any help, I'll try as many solution as I can an see which give me the best results.
I would like to thank everyone for your answers. Maxime > > > > >[That's just my opinion. I could be way off.] > > >-- > >These are my opinions, not necessarily my employer's. I hate spam. > > _______________________________________________ > questions mailing list > questions@lists.ntp.org > https://lists.ntp.org/mailman/listinfo/questions > -- Maxime Louvel 0044 7964 5555 80 43 Allen road Whitemore reans WV60AW Wolverhampton United Kingdom _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
