(clug-talk) Fun with Cron

Hopefully this might help someone else avoid some troubles.....

I had setup a cron job to do a backup.  I used the following line in my
crontab file:

* 02 * * * /root/cron/sysbackup

Well, it turns out that this will run the cron job every minute from 02:00am
to 02:59am.  It should have been:

00 02 * * * /root/cron/sysbackup

this fires only at 02:00am.

My backup does an rsync of my data files into another directory, then
creates an ISO image and writes it to a CDRW.  So, this process can take a
little while to happen.  To have the backup process run every minute was
causing all sorts of fun - but the server DID handle it.  I just couldn't
figure out why the CD would start ejecting and reloading every couple of
seconds at 2 in the morning.... (I wrote the backup script to NOT eject the
CD).

Anyways, hope this helps someone avoid similar issues.

Shawn