If you configured a dump device, a crash restore area, and the
scope of dump with
crashconf
then your machine will automatically dump a crash memory image after a panic or TOC.
If you haven't you still can either
savecrash
on reboot or later after reboot.
Since the crash dump device is usually taken from the swap device
(usually lvol2 if you use LVM layout)
you only have to take care to save the crash dump back to the filesystem
before swapouts will overwrite the dump area.
lvlnboot -v vg00
will show you the dump device.