Crontab and adjkerntz.
Ian Smith
smithi at nimnet.asn.au
Wed Aug 27 05:33:25 UTC 2008
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
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