Crontab's Black Holes (System hangs?)

[kangaroojack]

Hello everyone,

I've got a strange comportement with crontab.
Crontab seems to make some 'pauses' in his job.

I execute a script in this crontab to monitor each 15 minutes his comportement:

15,30,45,00 * * * * date >> /usr1/secu/ctr_cron

When I check the result of this, I've got some strange 'time holes' between the differents tasks.

Tue Feb 15 00:00:01 CET 2005
Tue Feb 15 00:15:00 CET 2005
Tue Feb 15 00:30:00 CET 2005
Tue Feb 15 00:45:00 CET 2005
Tue Feb 15 01:00:00 CET 2005

This time, all is clear ...

Fri Mar 4 01:00:00 CET 2005
Fri Mar 4 06:33:08 CET 2005

~5h lost

Sat Mar 5 01:15:00 CET 2005
Sat Mar 5 03:02:20 CET 2005

~1h45 lost

I've also created a litlle script that runs every 10 minutes.
Here is the action of my script.
date and ps -ef too who sleeps 600 sec and restart.That logged in a file.
I did that to not use cron an have a 'double' check of my system.
But when the 'time holes' occurs my script is locked aswell.

That occurs randomely at night and I cant certify if my scheduled jobs are well executed.
My own conclusion would be the system hang at night but I dont know why ...
Is anyone got an idee on the subject ?

PS:
My Sco OS version his: 5.0.6Ga
I've already patched my system with: OSS642a - Cron supplement (ver 1.0.0)

 

[motoslide]

Can you verify that the system hasn't actually rebooted during these time lapses? You can determine this either by looking at the system logs, or running the "who -b" command.
You also may wish to enable logging for cron. Do this by changing the variable "CRONLOG" in /etc/default/cron. You must restart cron (or simply reboot) for that setting to take affect. The log file will be /usr/lib/cron/cronlog.

Odd behavior, especially if the system isn't rebooting!!