exim4 CPU Issue

Hello,

I am running Debian Wheezy on my Linode 1G with the latest available Kernel.

Sometimes I leave a terminal session open with the server and monitor it using HTOP and frequently see exim4 maxing out the CPU, this happens every 30 minutes or so. The spike will last for between 1-3 minutes.

root@li147-104:~# du -sh /var/spool/exim4/*
4.0K    /var/spool/exim4/db
115M    /var/spool/exim4/input
58M     /var/spool/exim4/msglog
root@li147-104:~#

As you can see exim4 appears to be using a considerable amount of disk space too, so I am keen to get to the bottom of this issue. I don't have anything on the box that sends mail, so I exim4 should hardly be in use.

Any input appreciated.