On 2011-12-14, vijay agrawal <[email protected]> wrote: > David J Taylor wrote: > >> and let NTP take care of it all? Do you have some special >> requirement? > > I have some very time critical application which i assume may affect > while i sync my existing server with new GPS clock.
You should not be syncing your NTP to a single time source unless it is one that you control. If your application is time sensitive you should provide your ntpd with no less than 4 time sources for robustness and redundancy. > My most worry part is that if there is async with server and clock, > then they may affect the other application or clock may reject the > sync request with existing server. Hence i would like to sync in a > such way that it will gradually sync the clock rather than adruptly. > > Hence is thare any way to sync slowly? ntpd slews the clock (i.e. adjusts the clock by speeding it up or slowing it down at the rate of 1/2 millisecond per second) in cases where the offset is no more than 128 milliseconds (ms). The clock is stepped only for offsets greater than 128 ms. ntpd can normally keep your clock well within 10 ms of WAN (e.g. Internet) time servers, 5 ms of a LAN time server, and 0.01 ms of a direcly connected GPS ref-clock. Assuming that all of your time sources are ultimately synced to UTC the differences between them will be well within the slew/step threshold and your application won't notice a change in "sys_peer" (i.e. the time source you are "synced" to). -- Steve Kostecke <[email protected]> NTP Public Services Project - http://support.ntp.org/ _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
