I moved our hudson server (just zip up the $HUDSON_HOME directory and copy it across very easy) to a new redhat machine and the builds started failing with the error (Too many open files).
This indicates that my open file limit has been reached for my user. - check this with the
ulimit -n [this command check the users limit for open files ulimit -a to check all limits]
and lsof -p <pid> | wc -l [get the pid by doing a ps -ef | grep hudson]
To address this the easy way vi /etc/security/limits.conf and add/ edt the following lines (my was the default 1024):
* soft nofile 2048
* hard nofile 2048