Openfire ships with a 64Meg  JVM limit which is fine for testing purposes but you may find that you are using it all up.    I went round the forums a few times and found conflicting advice.

Anyhoo the instructions were close but seemed to give one massive red-herring which was they kept talking about OPENFIRE_OPTS in /etc/defaults/openfire which did not exist,   add it your self and Openfire will ignore it.    Where the data needs to go is in DEAMON_OPTS.

To cut a long story short you need to make /etc/defaults/openfire look like :

# Defaults for openfire initscript
# sourced by /etc/init.d/openfire
# installed at /etc/default/openfire by the maintainer scripts

#
# This is a POSIX shell fragment
#

# Additional options that are passed to the Daemon.
DAEMON_OPTS=”-Xms256m -Xmx512m”

This will tell the JRE to use a minimum of 256Meg RAM and limit it to 512Meg.

Hope this helps