[CentOS] crontab and/or anacrontab ?

Timothy Murphy gayleard at eircom.net
Thu Mar 11 16:17:13 UTC 2010


Alexander Dalloz wrote:

> let's take the case that you have a power failure or a scheduled
> maintenance with your system for instance in the early morning hours, from
> 03:00am - 05:00am. cron.daily is set by default to run at 04:02am. So in
> this case cron could not perform tasks like logwatch. logwatch will miss
> in such a case, *if* there wouldn't be anacron which takes over the task
> to run after the machine is up again (i.e. at 05:00am).

Thanks for your response.

Actually, I wouldn't mind in the slightest if cron.daily failed to run
because the machine was down at the nominated time.
It is not as though my world depends on cron.daily running every day.
I certainly would not run another program in case that happened.

> How anacron handles jobs is documentend in "man 8 anacron". It uses
> timestamp files in /var/spool/anacron/ to control, when a job was last
> performed and whether it is pending.

Actually, "man 8 anacron" does not say that.
It says "Anacron records the date in a special timestamp file",
but it doesn't say where that file is.

I see that there are actually files /var/spool/anacron/cron.daily , etc,
on my machine listing the last day anacron ran (20100311)
But it seems that this information is not used, in my case,
I don't know why.

As I said, this duplication seems to have started recently,
and I have taken no action on this machine for months
apart from running "sudo yum update",
so I assume some update had this effect.

I have a second CentOS machine where this duplication does not occur,
even though everything seems the same as on the first machine.






-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland



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