Ben, you have not yet stated what OS you are using. I think we need to know the flavour of windows you are using. If I read the mail thread, I see you have the following issues...
1. You have a problem with startup being too slow to achieve acceptable synchronisation. 2. Your windows boxes sometimes drift off a long way compared to the server. 3. You are now looking to patch up a poorly designed framework with software hacks to step the clocks back into alignment rather than fix the root cause of your troubles. My advice would be as follows... A. Decide what your startup AND synch criteria are (and let us know). If it cannot be met, you are wasting your time with NTP, and need to look elsewhere. B. Forget using localhost as a time source. More trouble than it is worth. C. Get a stable time source for your server. If you have internet, use it. If not, get a GPS based server and use it. As a rough guide, A Windows server will give you milliseconds quality reference clock. A Linux box will give you a Microseconds quality reference clock. D. Sort out your client PC's install of NTP. They are clearly not well installed or configured at this time. E. Monitor your client PC's (and indeed the server PC) over both the long term (days) and short term (minutes) to confirm both the startup time from boot and the stability are acceptable under regular use. Apologies if this is a little prescriptive and blunt (in my defence, I am a Yorkshireman), but we are a windows shop and have great success with ntp. regards pk -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of unruh Sent: Friday, 28 September 2012 5:20 AM To: [email protected] Subject: Re: [ntp:questions] NTP client configuration On 2012-09-27, Benjamin CABUT <[email protected]> wrote: > Hello, > > I don't car in my application to have the correct UTC time. > > What I care is that all my computers share exactly the same time. > Our application is not connected to internet. > So only time I can use as a reference is local clock of one computer. OK, look up "orphan mode". But again why are you suing a windows machine as your reference? Windows is not known for its timekeeping ability. Use for example one of your Linux machines instead. > > I can realy tell you that my client is not sync some times! > it happen in 2 ways: > -> when I start my computers, it need arround 5 minutes to be sync, it > is a problem for me ntpd is NOT designed for rapid convergence. 5 min is very fast as far as ntpd is concerned. > -> when one computer has heavy operation to do, then ntp client desync What do you mean "when one computer"? The server? a client? And what is "a heavy operation"? > > and I have offset that can be 2 seconds, and stay like this during > sereval minutes. You have other problems. ntpd is NOT designed to correct clocks which jump around by seconds. You need to get your clocks to behave themselves first so that their time does not jump around. > so It realy need a long time to ntp client to detect the big desync. > > I do not want to rewrite ntp. > ntpq gives the offset between clock of client and clock of server. > > As you say the best way for me is that ntp is working perfectly, but it > is not the case. Your idea and Mill's idea of "working perfectly" is different. He designed it so that it will correct clocks which run stably (loess than say 100PPM rate error always). It is NOT designed to hadle clocks whose rates can vary by more than that, or whose time can jump around. chrony (sorry does not run on Windows) does a bit better but again it would have trouble with your clocks as well. > I don't know how to improve this by configuration. Depends on what you mean by "improved". > > So I was just wondering if I could get the offset in my software to > solve my problem... I think you need to figure out what your problem is first. > > Regards. > > > > Le 27/09/2012 20:39, unruh a ?crit : >> On 2012-09-27, Benjamin CABUT <[email protected]> wrote: >>> Hello, >>> >>> We are using Meindberg NTP client and server. >>> >>> Our configuration is: >>> - 1 Computer under windows that is server >>> server 127.127.1.0 >> Why would you be using a windows machine as your server. Windows is not >> a great platform for time. >> >> And why in the worl would you have it be using the local refclock. That >> should never be used. Where in the world is that computer getting its >> time from? >> >> >> >>> broadcast 192.168.2.255 minpoll 4 maxpoll 4 iburst >>> disable auth >>> - several computer under linux + computers under windows, client of this >>> server: >>> server 192.168.2.250 minpoll 4 maxpoll 4 iburst >>> broadcastclient >>> disable auth >>> >>> >>> My problem is the following: >>> Mainly on windows computer, sometime, depending what the computer is >>> doing, there is a big offset between clients and server. >>> ("Big" for me is more than 500ms). >>> >>> I would like to know if it is possible to setup client so as soon as he >>> see offset>500ms, then client do a "fast" synch. (STEP). >> If ntpd sees an offset of 128ms and it believes this is a valid offset, >> it steps. >> >> >>> >>> Another way to solve my problem could be for me, to modify the source >>> code of my application in order to get this "offset" information inside >>> my code (C or C++ langage). then I could add this offset to the time of >>> the computer in order to be as much accurate as possible during the time >>> the offset is bigger than 500ms. >> ntpd does its best to get a small offset. What makes yo uthing your C >> program can do better? You have other problems. Worry about them, not >> about rewriting ntpd. >> >>> Do you have any solution? >>> >>> Regards. >>> >>> B CABUT >>> >> _______________________________________________ >> questions mailing list >> [email protected] >> http://lists.ntp.org/listinfo/questions >> >> >> > > _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
