[Dirvish] Logrotate mail log daily

[Keith Lofstrom]

Suggestion:  If you are getting a lot of spam, your mail log may
be getting very large from all the reject messages.  You should 
rotate your mail logs using the SUSE-style "dateext" extension,
and do it every evening.

I get about 50,000 lines of messages in my maillog every day,
almost entirely spam attempts.  Even with all sorts of filtering,
just keeping track of the *spam attempts" adds at least one line.
The mail log files were running about 105 megabytes a week, and
since the files differed every day, dirvish and rsync were creating
a new (and large) backup of the file every evening, like so:

Before:
 15  monday
 30  tuesday
 45  wednesday
 60  thursday
 75  friday
 90  saturday
105  sunday
---
315  MB/week new mail files backed up

By using a daily backup, and dateext, I am backing up only 15 new
MB per day, 105MB per week.  And yes, I do back up the mail logs,
it is critical to find missing bits of email, and keeping track
of system history. 

BTW, other spam filtering has cut the 15MB in half, so my backups
should last even longer.

Keith

-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs