Postfix log file grows too fast

Question

I've configure postfix for just sending emails. (I need it just for PHP mail() function). However, after one day running, And just a couple of sent emails, the log file is about 20 MB. Checking the /var/log/mail.log file, I find only lines similare to these:

Jun 19 18:23:02 myserver postfix/pickup[342]: 15BDD222C6: uid=33 from=<www-data>
Jun 19 18:23:02 myserver postfix/cleanup[370]: 15BDD222C6: message-id=<20130619182302.15BDD222C6@localhost>
Jun 19 18:23:02 myserver postfix/qmgr[343]: 15BDD222C6: from=<www-data@localhost>, size=547, nrcpt=1 (queue active)
Jun 19 18:23:02 myserver postfix/local[373]: 15BDD222C6: to=<www-data@localhost>, orig_to=<www-data>, relay=local, delay=0.02, delays=0.02/0/0/0.01, dsn=2.0.0, status=sent (delivered to mailbox)
Jun 19 18:23:02 myserver postfix/qmgr[343]: 15BDD222C6: removed
Jun 19 18:23:02 myserver postfix/pickup[342]: 1ADD9222C6: uid=33 from=<www-data>
Jun 19 18:23:02 myserver postfix/cleanup[370]: 1ADD9222C6: message-id=<20130619182302.1ADD9222C6@localhost>
Jun 19 18:23:02 myserver postfix/qmgr[343]: 1ADD9222C6: from=<www-data@localhost>, size=544, nrcpt=1 (queue active)
Jun 19 18:23:02 myserver postfix/local[374]: 1ADD9222C6: to=<www-data@localhost>, orig_to=<www-data>, relay=local, delay=0.01, delays=0.01/0/0/0, dsn=2.0.0, status=sent (delivered to mailbox)
Jun 19 18:23:02 myserver postfix/qmgr[343]: 1ADD9222C6: removed

A bigger sample: http://pastebin.com/xbE6mQye

Not sure what is the cause, I've been doing some research on internet, with no results.

If maybe this is a confirguration error I'd like to know how to reduce the logging and/or to log only relevant info.

This is my main.cf file And my master.cf file

Thanks in advance.

Answer 1

judging by the sender being www-data, it is some php script. (it's a guess though)

Answer 2

This is error was caused by a cron job run as www-data that always returned a string, so, the cron job generated a new mail for it.

The solution was to change the script being run by cron in order to return always an empty string unless it is absolutely necessary.

Thanks you everybody.

Answer 3

In my case was fail2ban that was sending mails to root every minute because of bruteforce attempts, so in this cases take a look at /var/mail/ directory and see if you find something bigger than it's should be.

Another thing to check is mailq as maybe something got stuck in it and continue to try to be sent.