Queue Building

[Mehul Choksi]

We have set up the qmail server using Adam McKenna’s Qmail-HOWTO V2 and it is working fine in normal condition. The purpose is to introduce qmail as an SMTP server in outbound email distribution system – just to send a million mails daily to subscribed users. We tested the performance of the qmail by sending a few thousands mails to non-existent email-ids and to bounce back to another mail server. Strangely enough, qmail just built up a huge queue, without even preprocessing. Once the application stopped pumping to the Qmail server, it started processing and clearing queue, which took very long. Is it a normal behavior (since all the email addresses were non-existent) or are we missing something somewhere? Concurrency is set to 120 for local and remote.   Any help/suggestions would be greatly appreciated.   Regards, Mehul.