Configuration

To configure the connection to Cassandra, you must provide the location and port of an initial contact node in your Cassandra cluster. This can be done via environment properties (or Java system properties). Use the names CASSANDRA_CONTACT_PORT(cassandra.contactPort) and CASSANDRA_CONTACT_ADDRESS(cassandra.contactAddress) (subject to change < 1.0). These default to localhost and 9042. Additionally, you may configure the size (in bytes) of chunk used for binary storage as CASSANDRA_MAX_CHUNK_SIZE(cassandra.maxChunkSize).

It is also possible to adjust consistency settings for read and write for binary and RDF data, all independently. The configuration keys are as follows:

Data category	READ	WRITE
Binary	CASSANDRA_BINARY_READ_CONSISTENCY (cassandra.binaryReadConsistency)	CASSANDRA_BINARY_WRITE_CONSISTENCY (cassandra.binaryWriteConsistency)
RDF	CASSANDRA_RDF_READ_CONSISTENCY (cassandra.rdfReadConsistency)	CASSANDRA_RDF_WRITE_CONSISTENCY (cassandra.rdfWriteConsistency)

and values are drawn from the usual Cassandra options. The default value for each consistency level is ONE.

Persistent configuration

You may also use a JSON document for these settings. Use TRELLIS_CONFIG_FILE (configurationFile) to use a file or TRELLIS_CONFIG_URL (configurationUrl) to use a document loaded from an arbitrary URL. The document should be a simple object with keys using the same names as system properties shown above (cassandra.contactPort, cassandra.contactAddress, etc.).