Message packets are probably what you’'re most interested in. Presence packets communicate the presence of users and IQ packets are used to send commands to and from the server. You might wish to check out the XMPP protocol for more details.
What were the values for the audit settings before you made the change? Knowing that will help us test for possible bugs.
I’'m not sure what the upper threshold is on these values:
Maximum size of all files (MB): 2048
Maximum file size (MB): 30
But when I set them to 2048 and 16 respectively yesterday, my log stayed at about 1kb and only showed the most recent entries. Immediately after I changed them back to 1000 and 10 (defaults) respectively, it all started working again just fine. Again, I’'m not sure what the upper limit is, but start by putting them back to defaults – 1000 / 10.