ntp.drift(4)ntp.drift(4)NAMEntp.drift - Network Time Protocol (NTP) drift file
DESCRIPTION
When the NTP daemon (xntpd) is first started, it computes the error in
the intrinsic frequency of the clock on the computer it is running on.
This process usually takes about a day or two after the daemon is
started to compute a good estimate of this (and it needs a good esti‐
mate to synchronize closely to its server). Once the initial value is
computed, it will change only by relatively small amounts during the
course of continued operation.
The driftfile declaration should always be included in the ntp.conf
file. This provides xntpd with complete path name to a file in which
it can store the current value of the frequency error. That way, if
the daemon is stopped and restarted, it can reinitialize itself to the
previous estimate without spending time recomputing the frequency esti‐
mate.
The ntp.drift file contains one line with the following format:
freq_offset flag Specifies the nominal frequency offset. DO NOT modify
this field. Specifies the method used to improve system clock accu‐
racy. Specifies that xntpd runs a Phase-Locked Loop (PLL) algorithm to
keep synchronized with other hosts. This is the default. Specifies
the use of the PLL algorithm in the kernel. This requires the NTP_TIME
kernel option. After the option is configured in the kernel, edit the
ntp.drift file and change the flag value to 1.
See System Administration for information on the NTP_TIME kernel
option.
FILES
Conventional name of the drift file
RELATED INFORMATION
Commands: ntpdate(8), ntpq(8), xntpd(8), xntpdc(8)
Files: ntp.conf(4)
Network Administration: Services, System Administration delim off
ntp.drift(4)