Crontab and adjkerntz.

[Ian Smith]

On Tue, 26 Aug 2008 16:05:13 +0200 Leslie Jensen <leslie at eskk.nu> wrote:

 > I have a machine that only runs during office hours. I've rescheduled 
 > the periodic jobs in crontab so that they run when the machine is on.
 > 
 > My question is can I reschedule the  adjkerntz job as well, without 
 > causing any problems? I'm concerned because the job is set to run 12 
 > times during night time, and I'm thinking that maybe it's a resource hog 
 > and therefore it's not advisible to run it when one uses the machine?
 >
 > # Adjust the time zone if the CMOS clock keeps local time, as opposed to
 > # UTC time.  See adjkerntz(8) for details.
 > 1,31    0-5     *       *       *       root    adjkerntz -a

Just to add a bit to what Andrew and Matthew rightly said:

sola# lastcomm -eE -f /var/account/acct.0 | grep adjkerntz
adjkerntz        -       root             __           0.02 es Wed Aug 27 03:01
adjkerntz        -       root             __           0.00 es Wed Aug 27 02:31
adjkerntz        -       root             __           0.00 es Wed Aug 27 02:01
adjkerntz        -       root             __           0.00 es Wed Aug 27 01:31
adjkerntz        -       root             __           0.00 es Wed Aug 27 01:01
adjkerntz        -       root             __           0.00 es Wed Aug 27 00:31
adjkerntz        -       root             __           0.03 es Wed Aug 27 00:01
adjkerntz        -       root             __           0.00 es Tue Aug 26 05:31
adjkerntz        -       root             __           0.00 es Tue Aug 26 05:01
adjkerntz        -       root             __           0.00 es Tue Aug 26 04:31
adjkerntz        -       root             __           0.00 es Tue Aug 26 04:01
adjkerntz        -       root             __           0.00 es Tue Aug 26 03:31

After 27+ days uptime, not a full second of CPU time:

  196 root        20    0  1316K     0K pause    0:00  0.00%  0.00% <adjkerntz>

and that's on a 300MHz Celeron .. so no, it's certainly no resource hog!

The 'adjkerntz -i' run at boot[1] should adjust for a TZ update occuring 
overnight, assuming CMOS has local time (ie /etc/wall_cmos_clock exists)

[1] actually run when going to multi-user, so with CMOS set to local 
time, you should remember to run 'adjkerntz -i' when working in single 
user mode (eg make installworld) if you want correct file timestamps.

cheers, Ian