Postfix and Linux

Berkeley DB issues

On RedHat Linux 7.0 you must install the db3-devel RPM before you can compile the Postfix source code.

Warning: do not use multiple Berkeley DB versions. Every Postfix program will dump core when it is built with a different Berkeley DB version than the version that is used by the system library routines. See the DB_README file for further information.

Procmail issues

On RedHat Linux 7.1 procmail no longer has permission to write the mail spool directory. Workaround: chmod 1777 /var/spool/mail.

Syslogd performance

LINUX syslogd uses synchronous writes by default. Because of this, syslogd can actually use more system resources than Postfix. To avoid such badness, disable synchronous mail logfile writes by editing /etc/syslog.conf and by prepending a - to the logfile name:

/etc/syslog.conf:
    mail.*                          -/var/log/mail.log

Send a "kill -HUP" to the syslogd to make the change effective.