HP-UX Reference (11i v2 07/12) - 1M System Administration Commands N-Z (vol 4)

xntpd(1M) xntpd(1M)

: synchronized to 15.13.115.194, stratum=1

: Previous time adjustment incomplete; residual -0.022223 sec

: Previous time adjustment incomplete; residual -0.020624 sec

: Previous time adjustment incomplete; residual -0.020222 sec

: Previous time adjustment incomplete; residual -0.020623 sec

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 adjust-

ment 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

/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