One of our servers here at Vivio is routinely scanned for PCI compliance purposes. Until just recently, we've been using FuseGuard (A Web Application Firewal, or "WAF"), to block intrusion attempts to our web application. With new PCI standards that force us to allow PCI scans through our WAF (or IDS or whatever), we had to allow these requests through, but that brought to light another, different, problem.
During the PCI scan, our Apache logs would get a lot of the following error messages:
[notice] jrApache[13857: 62679] returning error page for JRun too busy or out of memory
Initially we thought that since the message was coming from the JRun connector, that the issue had something to do with the connector. However, after quite a bit more research, we found it had to do with JRun itself, and the specific number of post parameters it's configured to accept. Any more then the default "100" post parameters, and you'll get the error you see above.
To change the number of post parameters, you will need to update your neo-runtime.xml file. For our case, ours was found here:
IMPORTANT: Editing this file isn't particularly easy. Opening it in VIM gives you a big wall of text.
By increasing the following parameter from 100 to 300, we were able to succesfully complete our PCI scan:
Hopefully this helps anyone else having this issue.