vanishing cron jobs

[Ian Bennett]

Using FreeNAS 9.10. I have a file cronfile with a single cron task which I register by running crontab cronfile from a terminal logged on as root. All goes well and a crontab -l shows the job registers just fine. It's a daily job and it runs perfectly... for a while. Out of nowhere, the job appears to simply vanish - running crontab -l shows an empty list! This has happened twice now in around a year.

Re-registering using crontab cronfile puts everything back in order and things are OK once more, but it's recently happened again. Anyone any idea why this might be the case? Am I missing something? Perhaps some background job that FreeNAS runs periodically (say every 6 months) is clobbering my manually registered cron task. Maybe I should use the GUI to set up cron rather than a manual crontab cronfile from a terminal.

If anyone can point me in the correct direction it would be much appreciated.

 

[danb35]

Maybe I should use the GUI to set up cron rather than a manual 'crontab cronfile' from a terminal.

Yes, I'd say so--this is the most likely source of what you're seeing. Especially if you're changing anything in the GUI around the time the cron job disappears.

 

[wblock]

It's important to remember that FreeNAS is an appliance. Many of the normal Unix settings are kept in a database. Making manual changes to configuration files can be overwritten exactly as described.

Maybe I should use the GUI to set up cron rather than a manual 'crontab cronfile' from a terminal.

Yes.

 

[DrKK]

Indeed. crontabs (on the appliance) are stored in the database. Any manual changes you make, at the CLI (instead of the GUI), will certainly die at any reboot/restart, and possibly sooner. If you want to add something to cron, you add it to the database, by adding it to the appropriate place in the GUI.

Of course, in a *JAIL*, that is not the case, and you would treat a jail as you would bare metal running FreeBSD, and thus, make your changes to the crontab in there manually.