The debian init script sets the heap dump file directly using the cassandra users home directory and the -H flag to the cassandra process1. The cassandra heap dump location can also be set in the cassandra-env.sh file using CASSANDRA_HEAPDUMP_DIR. Unfortunately the debian init heap dump location is based off the home directory of the cassandra user and cannot easily be changed. Also unfortunately if you do `ps aux | grep casandra` you can clearly see that the -H flag takes precedent over the value found in cassandra-env.sh. This makes it difficult to change the heap dump location for cassandra and is non-intuitive when the value is set in cassandra-env.sh why the heap dump does not actually end up in the correct place.