HP-UX Reference (11i v1 05/09) - 1M System Administration Commands N-Z (vol 4)

xntpd(1M) xntpd(1M)

But this does not mean that your system clock has been stepped. Only the

NTP daemon process has seen a

step in its notion of the current time (and this will be passed on to clients). The system time is being gradu-

ally adjusted in a series of

SLEW maneuvers, and the

SLEW rate is quite limited. Be warned that it can

take a long time for the system clock to reach nominal correctness, and much longer to stabilize. Each cpu

model is unique, but the maximum slew rate is typically about 40 milliseconds per second. Thus a

SLEW

adjustment of 411 seconds will take over 10,000 seconds (about 3 hours) to complete. A better approach

would be to run the

ntpdate command once at system startup, and accept the one STEP change that

comes with it. Then start the NTP

daemon process xntpd and it will never make a STEP as long as your

connection to the timesource is good. This method also overcomes the 1000 seconds problem. The

NTP

startup script /sbin/rc2.d/S660xntpd

will do this automatically if you conﬁgure the

NTPDATE_SERVER

variable in /etc/rc.config.d/netdamons

. A properly conﬁgured NTP

hierarchy with average networking (say 10Base-T) can run for years without ever making a STEP change.

AUTHOR

xntpd was developed by Dennis Ferguson at the University of Toronto.

Text amended by David Mills at the University of Delaware.

FILES

/etc/ntp.conf The default conﬁguration ﬁle

/etc/ntp.drift The default drift ﬁle

/etc/ntp.keys The default key ﬁle