I sometimes run into bugs or issues with Apache HTTPD that require having the server create a core dump file. For example, today I noticed my error_log showing this:
[notice] child pid 11413 exit signal Segmentation fault (11)
I found a helpful page on the Apache website with instructions. They suggest that a core dump will be generated simply by adding the following to your httpd.conf file and restarting:
CoreDumpDirectory /tmp
After adding that setting and restarting, Apache still would not dump core. Same segmentation fault, no core.