These are some commands to check if your mail queue flooded with mails.

To see how many mails are in the queue:

exim -bpc

To get some more details about the queued mails:

exim -bp

To backup your Bayes data run:

sa-learn --backup > backup.txt

This will save all Bayes data to a plain text file called backup.txt.
To restore these data run:

sa-learn --restore backup.txt

The following value in exim.conf limits the number of recipients per message (default value is 0 which means no limit at all):

recipients_max = count

If count > 0 exim stops delivering the mail after count recipients.

This is a tutorial how to setup a server for mail and web.

It is based on the following components:
OS: Linux CentOS 5.2
HTTP Server: Lighttpd 1.4.19, PHP 5.1.6
Database: MySQL 5.045
Mailserver: Exim 4.63 with Vexim 2.2.1, Spamassassin 3.2.4, Clamav 0.94
IMAP/Pop3 Server: 1.07