What is the core file in the /var/log generated by? I have one that is 500mb or so, and I want to either set it up to be rotated in logrotate.d if it's a log file, or figure out why it's there if not.
A fatal error in a program automatically triggers a core dump, and by extension the phrase "to dump core" has come to mean, in many cases, any fatal error. A core dump is often a useful tool for a programmer seeking to isolate and identify an error in an application/service. You can delete these files in your /var/log if you want, unless you wish to logrotate them for future diagnosis.
Core dumps is from prgrams that exit bad and leave the core dump for investigations, I think
Worse is that hackers are doing stuff to make core dumps and get root access, this is possible on like Centos 4.4 if kernel is not upgraded, and others systems to.