We're trying some load testing on our Java web app running on Tomcat. Right now, I have a simple test program that hits Tomcat with 500 separate users (threads) at once and starts using the site, doing things that interact with the database (Oracle), etc. We've adjusted our Oracle database sessions (connections) and listener sessions accordingly, so we don't get error messages from those when we pound the site/db really hard. However, now we're seeing something that I think is related to Linux.

Tue Feb 01 16:53:08 CST 2005 Error Running SQL: java.sql.SQLException: Io exception: The Network Adapter could not establish the connection

This popped up when running a query, but if you look closely, the SQLException is throwing an exception related to IO stuff, so it seems like the error could be happening on a lower level (Linux trying to use resources for connecting to the network or something like that?). I mean, could the load tester be pounding everything so fast that Linux's network IO stuff could get tied up?