HowtoMatrix

This document describes how to install a PureFTPd server that uses
virtual users from a MySQL database instead of real system users. This
is much more performant and allows to have thousands of ftp users on a
single machine. In addition to that I will show the use of quota and
upload/download bandwidth limits with this setup. Passwords will be
stored encrypted as MD5 strings in the database.

Read more at HowtoForge