This chapter covers the two most important tools an administrator needs when maintaining a qmail server over the long term: analyzing the log files to locate problems, and on that basis finding ways to improve qmail's performance.
When analyzing qmail's operation for almost any purpose, the first place to begin looking is in qmail's log files. In a standard qmail setup, there are two sources of log files: one for qmail-send
and one for qmail-smtpd
. By default, these contain both useful information for tracking down individual messages and useful information for analyzing qmail's performance.
The log output of both qmail-send
and qmail-smtpd
is organized in a simple way, though it can easily become confusing.