By default Squid leaves core files in the directory from where
it was started. If you set 'coredump_dir' to a directory
that exists, Squid will chdir() to that directory at startup
and coredump files will be left there.
In addition to changing the directory, the process permissions are updated
to enable process tracing and/or coredump file generation. The details are
OS-specific, but look for prctl(2) PR_SET_DUMPABLE and procctl(2)
PROC_TRACE_CTL documentation as guiding examples.
# Leave coredumps in the first cache dir
coredump_dir /usr/local/squid/var/cache/squid