Suppose that you know how many users will hit your site hosted by tomcat 5.5 simultaneously, you can use the following math to compute maxThread (http workers) you will need:
MaxThread = 1.5 * Max Concurrent Request + 7
The max thread count gives tomcat a guideline how many worker threads it would create. In reality tomcat will not create these many. If the load proportion reaches 66%, it will insert "connection: close" in the HTTP header to ask client to close the connection. If your browser does not open a new connection for following request, users start seeing errors.
