Correction: crash(8), not crash(9).
Additional info: crash dumps will be saved to disk for post mortem analysis, if:
- The kernel is able to function sufficiently to dump RAM to swap space on command from ddb or automatically, depending on sysctl settings.
- There is sufficient swap space available
- There is sufficient disk space available for the dump to be saved from swap upon reboot -- rc(8) calls savecore(8) and the default directory used is /var/crash.