A core file created when ever a program terminates unexpectedly and its also useful for determining what caused the termination. In many Linux server by default they do not produce core files when programs crash or terminates unexpectedly.

On  most of the Linux server core file size limitation is set to 0.You can check the core file size limit set in server by using following command.

root@gunjan [~]# ulimit -c
1000000

In above command core file size limit is 1000000 if output occur empty then it means core file size limit haven’t set on server and you can set it as

root@gunjan [~]# ulimit -c 1000000

or

root@gunjan [~]# ulimit -c unlimited

If you want to test core file limit is working on your server or not? then run following command

kill -s SIGSEGV $$

This above command will crashes your shell and produces core file in the current directory. as core.*

If core file is taking lots of disk space on server and you want to disable it then follow the steps one by one.

root@gunjan [~]#which httpd

/usr/sbin/httpd

root@gunjan [~]#pico /usr/sbin/httpd

And following line in /usr/sbin/httpd

ulimit -c 0

And then restart the Apache server