At umich.edu, we provide xntpd style time service from the database
servers, and we strongly urge that people run "afsd -nosettime"
When the afs cache manager adjusts the time, it does so in one-second
increments, which could cause applications (such as make) to act strangely.
When xntpd adjusts the time, it speeds up or slows down the system clock,
so there are never any sudden forward or backwards jumps in time.
xntpd is also much better at setting the clock accurately,
usually at least down to millisecond precision. Basically, it's
just much better at setting the clock.
For a long while, we also had one MVS AFS file server. In most
MVS installations, including ours, the time is set by the "eyeball"
method. A human looks at a clock, then sets the system wide TODR.
In older 370's, there was even a hardware switch that the operator
could use to lock the OS out from changing the TODR after it was set.
What this all meant was the MVS server was often 20-30 seconds "off"
from everything else, and couldn't easily be fixed.
-Marcus
