Check the progam associated to a core file, and all dependent libraries:

root@nim /root # /usr/lib/ras/check_core /export/lpp_source/base-aix61tl6/core
/usr/lib/libc.a
/usr/lib/libodm.a
/usr/lib/libinstall.a
/usr/lib/libcfg.a
/usr/lib/libcrypt.a
/usr/lib/nls/loc/en_US
/usr/lib/libi18n.a
/usr/lib/libiconv.a
installp

The following file is not a core file, just a file named “core”:

root@nim /root # /usr/lib/ras/check_core /etc/security/aixpert/core
check_core:: Error 0

In order to centralize cores at one place

- Create a dedicated filesystem, with full permissions for everybody

root@nim /root # mklv -tjfs2 -y corelv rootvg 1G
root@nim /root # crfs -vjfs2 -m /var/core -d corelv -Ayes -a log=INLINE
root@nim /root # mount /var/core
root@nim /root # chmod 777 /var/core

- Change the path to centralize all cores for all user into /var/core; this command will set the default parameters for cores in /etc/security/user. User cores are persistent parameters.

root@nim /root # lscore
compression: off
path specification: off
corefile location: not set
naming specification: off
root@nim /root # chcore -c on -p on -l /var/core -n on -d
root@nim /root # lscore
compression: on
path specification: on
corefile location: /var/core
naming specification: on

- While it's not persistent, system core have to be set at every start by adding an entry into /etc/inittab

root@nim /root # syscorepath -g

root@nim /root # echo '#!/bin/ksh
# Set core path for system
if [[ "$(uname -W)" == "0" ]]
then
  if [ -d /var/core ]
  then
    syscorepath -p /var/core
    if [ $? -eq 0 ]
    then
      echo "syscorepath OK"
    fi
  else
    echo "**** ERROR /var/core doesn t exist"
  fi
fi
' > /etc/rc.syscore
root@nim /root # chmod +x /etc/rc.syscore
root@nim /root # mkitab "syscore:23:once:/etc/rc.syscore > /dev/console 2>&1"
root@nim /root # /etc/rc.syscore
root@nim /root # syscorepath -g
/var/core

- If required change user core parameter to take the default value. Here for example for the root user.

root@nim /root # cat /etc/security/limits
....
default:
        fsize = 2097151
        core = 2097151
        cpu = -1
        data = 262144
        rss = 65536
        stack = 65536
        nofiles = 2000

root:
        fsize = -1
        core = 0
        data = 524288
root@nim /root # chuser -R files -a core='' root

If enabled, fullcore will increase the size of each core file written on the system by including additional information such as shared memory segments that might be needed in order to find the cause of a problem, and additional data needed when debugging multi-threaded programs.

To enable full core:

chdev -l sys0 -a fullcore=true

Allow root user to produce cores, if ulimit -c is 0 then no core allowed

root@nim /root # ulimit -c
0
root@nim /root # lsuser -a core root
0
root@nim /root # ulimit -c 2097151
root@nim /root # while true
do
sleep 14
done &
[1]     8257538
root@nim /root # kill -3 8257538
root@nim /root # ls -l /var/core
total 48
-rw-------    1 root     system        11159 Oct 18 12:02 core.8257538.18100246.Z
drwxr-xr-x    2 root     system          256 May 19 2016  lost+found
[1] + Quit(coredump)           while true;do;sleep 14;done &
root@nim /var/core # uncompress /var/core/core.8257538.18100246.Z
root@nim /var/core # /usr/lib/ras/check_core /var/core/core.8257538.18100246
/usr/lib/libc.a
/usr/lib/libiconv.a
/usr/lib/libcrypt.a
/usr/lib/nls/loc/en_US__64
/usr/lib/libi18n.a
/usr/ccs/bin/usla64
ksh93