在 2013年11月26日星期二UTC+8上午10时34分09秒，[email protected]写道： > 在 2013年11月25日星期一UTC+8下午10时36分19秒，Martin Burnicki写道： > > > [email protected] wrote: > hello : > I had recently start a work > > about ntp service ,my friends and me use > windows and linux to sync time > > in ntp.we could use w32time service to > sync linux in ntp. I hope the > > Linux machine is the NTP server, and your Windows machine is the NTP > > client. Linux and other Unix-like systems are usually much better > > timekeepers than Windows is. > In windows we could I found that in the > > registry： > > > HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\ > > > MaxAllowedPhaseOffset may be could set the offset time between the > local > > time and the server that they will be synchronize. If out of > range of > > MaxAllowedPhaseOffset in seconds ,they synchronize,otherwise > not. But I > > have a question that Is there a paremeter in ntp service > that control the > > offset like in registry above in windows. As has been noted by others here, > > ntpd tries to slew the system time smoothly if the estimated time > > difference is below a certain limit, and just steps the system time if if > > the determined offset exceeds this limit for some time. The limit is > > usually 128 ms, but can be changed. Unfortunately you don't tell which > > Windows version and which version of the NTP service you are using. If you > > are encountering problems getting the Windows time adjusted properly by > > ntpd then a a Windows bug can be the reason why. Some Windows versions > > don't apply small time adjustments to the system time at all. For example, > > if NTP applies an adjustment less than 16 ticks to the Windows time this is > > simply ignored by Windows. However, NTP expects the adjustment to have some > > effect, but if there is no effect then the next time comparison yields a > > much larger difference than expected, and thus causes another adjustment > > which is probably larger than necessary. As a summary this can cause large > > swings in the time adjustment values. A developer version of the NTP > > package contains a workaround for this Windows bug. The report and fix are > > discussed here: NTP Bug 2328 - Vista/Win7 time keeping inaccurate and > > erratic https://bugs.ntp.org/show_bug.cgi?id=2328 The bug report contains a > > link to the Microsoft support web page explaining the bug: > > SetSystemTimeAdjustment May Lose Adjustments Less than 16 > > http://support.microsoft.com/kb/2537623 Even though the MS report only > > mentions Windows 7, the Windows Server 2008 kernel is similar to Windows 7 > > and has probably the same bug. So if you want to give it a try you can > > download a developer version of the NTP package which includes a workaround > > here: http://support.ntp.org/people/burnicki/windows/ You should try the > > release version first. Just unzip the ZIP archive, stop the NTP service, > > copy all extracted files over the files in your NTP installation directory > > (e.g. C:\Program Files (x86)\NTP\bin\), and restart the NTP service. Also > > all newer development versions of the NTP binaries should include this. We > > have found that this version has greatly improved the resulting accuracy on > > Windows 7 and Windows Server 2008 installations. Please note under Windows > > you should configure all upstream servers with a line reading server > > aa.bb.cc.dd iburst minpoll 6 maxpoll 6 where aa.bb.cc.dd has to be replaced > > with the host name or IP address of your NTP server. Please don't use > > polling intervals below 6 with the developer version since this prevents > > the workaround from working correctly as discussed in the bug report. Also, > > if you don't limit the upper bounds of the polling interval by "maxpoll 6" > > you may run into this bug: NTP Bug 2341 - ntpd fails to keep up with clock > > drift at poll > 7 http://bugs.ntp.org/show_bug.cgi?id=2341 On the other > > hand, the developer version above configured with regard to the hints above > > has fixed the timekeeping and significantly increase the time accuracy in a > > number of installations of Windows 7 and Windows server 2008. Hope this > > helps. Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany > > > > Windows system :Windows Server 2008 R2; > > Windows Server 2008 R2 ----NTP sync-----Linux Cent OS 6.2-----w32TIME > Sync------Windows XP/7
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