I have ran redhat enterprise 3.0 for quite a while before upgrading to centos 4.3, without any freezes or server hangs.

Once I installed and configured centos 4.3, it seems that crond is hanging the box. Each time that this happens, it is always the last entry in /var/log/messages as well as /var/log/cron (right as the box freezes) as follows:


Jul 6 02:01:01 server_name crond(pam_unix)[5465]: session closed for user root

This happens intermittently, once a week, or even 2 days in a row.
This has stopped now that crond has been shut down…

Any thoughts?

Any thoughts?
My first thought is what breaks by disabling crond: for instance logrotate is run from cronjob. Also stopping crond isn't a solution, it's just like taking painkillers: most likely you're only remedying symptoms, not the cause.


Jul 6 02:01:01 server_name crond(pam_unix)[5465]: session closed for user root
This happens intermittently, once a week, or even 2 days in a row.
Start by examining the commands from your crontabs.

crond was only disabled temporarily to verify that it was in fact causing the server lock-ups.

Prior to that, most cronjobs were disabled during the troubleshooting process. It turns out that lockups occur during any given valid cron command. It happens with any cronjob, at any time. This seems to be an issue with cron, as the same cronjobs run without issue on the same box when booted up into RH Enterprise 3.0...

Also, the MB is new, and we monitor the temps via lm_sensors so it is not an overheating-related issue.

It turns out that lockups occur during any given valid cron command. It happens with any cronjob, at any time. This seems to be an issue with cron, as the same cronjobs run without issue on the same box when booted up into RH Enterprise 3.0...
If it is crond itself you could try and replace the crond rpm for the one from RHEL3.

Sounds like the best direction to go in at this point... When this first occurred, we updated cron using yum, but that did not help.

Also, another consideration not mentioned before is that we use webmin to update/create some cron jobs and crontab at the cmd prompt for others.

Thanks!