Configuring the heap dump directory

Analyzing the heap dump file can help troubleshoot memory problems. Cassandra starts Java with the option -XX:+HeapDumpOnOutOfMemoryError. Using this option triggers a heap dump in the event of an out-of-memory condition. The heap dump file consists of references to objects that cause the heap to overflow. By default, Cassandra puts the file a subdirectory of the working, root directory when running as a service. If Cassandra does not have write permission to the root directory, the heap dump fails. If the root directory is too small to accommodate the heap dump, the server crashes.

For a heap dump to succeed and to prevent crashes, configure a heap dump directory that meets these requirements:

• Accessible to Cassandra for writing
• Large enough to accommodate a heap dump

Base the size of the directory on the value of the Java -mx option.