We are getting a high number of these process running, which causes our system load to climb extremely high (sometimes over 100) until we kill the processes (using "killall find"). They seem to start back on their own and yesterday we saw 50 or more of them.

This is an example of the process that is running:

zimbra    6053 22.4  0.0  23320 13004 ?        Ss   09:31   0:02 find /opt/zimbra/convertd/convert/convert -mmin +20 -type f -exec rm -f {} ;
Does anyone have any idea what these are and what would be causing them?