Alexandre Carrausse schrieb: > I am still not getting the purpose of this file. Is the value inside this > file supposed to change? Or is this value configured by someone for good. > Should I become worried if I see some strange values in those files? > What is the meaning of a high value? Is it good or bad if the value is > 0.000? >
The ntp.drift file stores the frequency error of the local system clock, as compared to the True Frequency (1 second per second) as defined by reference clock sources or external, higher-stratum NTP servers. It's used if NTP is stopped and restarted for any reason, so that NTP has a good idea of what the system clock frequency error might be and can concentrate on correcting phase error. The frequency error of the local system clock varies due to temperature changes and ageing, therefore NTP stores a new value in ntp.drift periodically (once per hour according to the documentation). You don't normally have to touch it -- it all happens automatically. Read more about this here: http://www.eecis.udel.edu/~mills/ntp/html/debug.html. At the moment, my five NTP servers (all Sun SPARC hardware) have the following values in their ntp.drift files: -93.879 -22.856 13.594 -54.257 2.227 What do you mean by 'strange values'? A high value (modulus) means that the free-running frequency of your system's local clock is a long way off nominal. A high value is not necessarily cause for worry; a value that changes a lot is. Statistically speaking, it's just about impossible that a real-life NTP server that's synchronised to an external time source (UTC) will ever have the value 0.000 in etc.drift. If you see 0.000 under those circumstances, I would bet that NTP is not running correctly. However: If you are running an isolated NTP network with no refclocks and with no access to external NTP servers, your highest-stratum server will be using its own system clock to synchronize its own system clock, and obviously its frequency error will be 0.000. Paul _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
