I recently saw this issue on a AM 6 server that was running just as test for about a week. Can we remove the caveat that this is only for Embedded DS, I've had other cases too where a customer was running into max file handles with a non-embededded Configuration/data store.
7. Check the file descriptors:
cat /proc/<tomcat pid>/limit | grep 'open files'
The Correct file is actually limits with an 's'.