From LinuxReviews

Note: These steps are for Fedora Core, but should work on other Linux systems as well.

What are core-dump?

When a program crashes then it may leave a core which can be used to figure out exactly why the program crashed - which is specially useful if you are a programmer.

Core dumps are disabled by default on many Linux distributions as core-dumping on production machines is generally considered a bad idea.

HOWTO enable core-dumps

To enable core dumps for all daemon, please follow these steps:

Edit the /etc/profile. At line 26 of the file, replace this line:

ulimit -S -c 0 > /dev/null 2>&1

with this line:

ulimit -c unlimited >/dev/null 2>&1

Replace this line (around line 138 on Fedora) in /etc/init.d/functions

ulimit -S -c 0 >/dev/null 2>&1

with this:

ulimit -S -c ${DAEMON_COREFILE_LIMIT:-0} >/dev/null 2>&1

(this is now default on Fedora Core <3)

Enable core-dumping globally by editing the /etc/sysconfig/init file and adding the line:

DAEMON_COREFILE_LIMIT='unlimited'

Enable it for specific daemons by adding this line in the /etc/sysconfig/$daemon:

DAEMON_COREFILE_LIMIT='unlimited'

Optionally, enable core dump for SUID programs:

echo 1 > /proc/sys/kernel/suid_dumpable

Edit the /etc/sysctl.conf and add the following:

kernel.suid_dumpable = 1
kernel.core_uses_pid = 1

Then reload the settings in /etc/sysctl.conf:

sysctl -p