Our Linux systems run logwatch(8) utility by default. On a RedHat/CentOS/SL system, Logwatch is called by the
/etc/cron.daily/ cronjob, which then sends a daily email with the results. These emails have a subject like:
Subject: Logwatch for $HOSTNAME
The problem is that by default these daily emails are too noisy and contain a lot of superfluous information (HTTP errors, daily disk usage, etc) which are already monitored by other services (Nagios, Cacti, central syslog, etc). For 100 systems, the email load is unbearable. People ignore the emails, which means that we may miss problems which are picked up by logwatch.
How can I reduce the amount of noise generated by logwatch, but still use logwatch to notify us of significant problems?
I'll post my own answer below, but I would like to see what others have done.
Note: I have a similar question regarding FreeBSD, at FreeBSD: periodic(8) is too noisy. How can I control the noise level?