Howtoforge published a guide about Virtual Hosting with PureFTPd and MySQL on Fedora 7

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.

Virtual Hosting With PureFTPd And MySQL (Incl. Quota And Bandwidth Management)