Distributed James Server — cassandra.properties

Consult this example to get some examples and hints.

Configuration

Here are generic properties:

Table 1. cassandra.properties content
Property name	explanation
cassandra.nodes	List of some nodes of the cassandra’s cluster in following format host:port or host, if the port is not specified we use 9042
cassandra.keyspace.create	Indicate if the keyspace should be created by James. Optional, default value: false If set to true James will attempt to create the keyspace when starting up.
cassandra.keyspace	Is the name of the keyspace used by James. Optional, default value: apache_james
cassandra.user	Username used as a credential for contacting Cassandra cluster. Optional, default is absent, required if cassandra.password is supplied
cassandra.password	Password used as a credential for contacting Cassandra cluster. Optional, default is absent, required if <strong>cassandra.user</strong> is supplied
cassandra.ssl	Whether SSL should be enabled on the communications with Cassandra cluster. Optional, defaults to false. The keystore used for trusting SSL server socket can be set via JSSE system properties as explained on Cassandra driver manual.
cassandra.replication.factor	Is the replication factor used upon keyspace creation. Modifying this property while the keyspace already exists will have no effect. Optional. Default value 1.
cassandra.query.logger.constant.threshold	If specified all queries that take more than the given integer in millisecond will be considered slow and logged. If not specified by default a DynamicThresholdQueryLogger will be used (see above)
cassandra.query.slow.query.latency.threshold.percentile	Default is com.datastax.driver.core.QueryLogger.DEFAULT_SLOW_QUERY_THRESHOLD_PERCENTILE. The latency percentile beyond which queries are considered 'slow' and will be logged. If you specify cassandra.query.logger.constant.threshold, you should not specify this property
cassandra.query.logger.max.query.string.length	Default is com.datastax.driver.core.QueryLogger.DEFAULT_MAX_QUERY_STRING.LENGTH. The maximum length of a CQL query string that can be logged verbatim by the cassandra driver
cassandra.query.logger.max.logged.parameters	Default is com.datastax.driver.core.QueryLogger.DEFAULT_MAX_LOGGED_PARAMETERS. The maximum number of query parameters that can be logged by the cassandra driver
cassandra.query.logger.max.parameter.value.length	Default is com.datastax.driver.core.QueryLogger.DEFAULT_MAX_PARAMETER_VALUE_LENGTH. The maximum length of query parameter value that can be logged by the cassandra driver
cassandra.readTimeoutMillis	Optional. If specified defines the Cassandra driver read timeout.
cassandra.consistency_level.regular	Optional. Allows specifying the driver default consistency level. Defaults to QUORUM. Allowed values: QUORUM, LOCAL_QUORUM, or EACH_QUORUM
cassandra.consistency_level.lightweight_transaction	Optional. Allows specifying the driver serial consistency level. Defaults to SERIAL. Allowed values: SERIAL or LOCAL_SERIAL
cassandra.local.dc	Optional. Allows specifying the local DC as part of the load balancing policy. Specifying it would result in the use of `new TokenAwarePolicy(DCAwareRoundRobinPolicy.builder().withLocalDc(value).build())` as a LoadBalancingPolicy. This value is useful in a multi-DC Cassandra setup. Be aware of limitation of multi-DC setups for James Not specifying this value results in the driver’s default load balancing policy to be used.
optimistic.consistency.level.enabled	Optional. Allows specifying consistency level ONE for reads in Cassandra BlobStore. Falls back to default read consistency level if the blob is missing. Defaults to false.

Pooling options

Here are some properties for Pooling options:

# Read com.datastax.driver.core.PoolingOptions for knowing defaults value
# No value here will default to driver's default value

# cassandra.pooling.local.max.connections=8
# cassandra.pooling.local.max.requests=128
## In ms. Should be higher than socket read timeout
# cassandra.pooling.timeout=5000
## In seconds.
# cassandra.pooling.heartbeat.timeout=30
# cassandra.pooling.max.queue.size=256

Table 2. cassandra.properties content
Property name	explanation
cassandra.pooling.local.max.connections	Optional. Defaults to 8. If specified defines the Cassandra maximum number of connections to hosts (remote and local).
cassandra.pooling.local.max.requests	Optional. Defaults to 128. If specified defines the Cassandra maximum number of concurrent requests per connection.
cassandra.pooling.timeout	Optional. Defaults to 5000 (ms). If specified defines the Cassandra timeout for waiting in the pool queue. Should be higher than sockets timeout.
cassandra.pooling.heartbeat.timeout	Optional. Defaults to 30 (s). If specified defines the Cassandra heartbeat timeout.
cassandra.pooling.max.queue.size	Optional. Defaults to 256. If specified defines the Cassandra maximum size of the connection pool queue.

If you want more explanation about Cassandra configuration, you should visit the dedicated documentation.

Cassandra Mailbox Configuration

cassandra.properties file furthermore expose some options to tune the Cassandra Mailbox behaviour.

Table 3. cassandra.properties content
Property name	explanation
mailbox.read.repair.chance	Optional. Defaults to 0.1 (10% chance). Must be between 0 and 1 (inclusive). Controls the probability of doing a read-repair upon mailbox read.
mailbox.read.repair.chance	Optional. Defaults to 0.1 (10% chance). Must be between 0 and 1 (inclusive). Controls the probability of doing a read-repair upon mailbox read.
mailbox.counters.read.repair.chance.max	Optional. Defaults to 0.1 (10% chance). Must be between 0 and 1 (inclusive). Controls the probability of doing a read-repair upon mailbox counters read. Formula: read_repair_chance = min(mailbox.counters.read.repair.chance.max, (100/unseens)*mailbox.counters.read.repair.chance.one.hundred)
mailbox.counters.read.repair.chance.one.hundred	Optional. Defaults to 0.01 (1% chance). Must be between 0 and 1 (inclusive). Controls the probability of doing a read-repair upon mailbox counters read. Formula: read_repair_chance = min(mailbox.counters.read.repair.chance.max, (100/unseens)*mailbox.counters.read.repair.chance.one.hundred)
mailbox.max.retry.acl	Optional. Defaults to 1000. Controls the number of retries upon Cassandra ACL updates.
mailbox.max.retry.modseq	Optional. Defaults to 100000. Controls the number of retries upon Cassandra ModSeq generation.
mailbox.max.retry.uid	Optional. Defaults to 100000. Controls the number of retries upon Cassandra Uid generation.
mailbox.max.retry.message.flags.update	Optional. Defaults to 1000. Controls the number of retries upon Cassandra flags update, in MessageMapper.
mailbox.max.retry.message.id.flags.update	Optional. Defaults to 1000. Controls the number of retries upon Cassandra flags update, in MessageIdMapper.
fetch.advance.row.count	Optional. Defaults to 1000. Controls the number of remaining rows we should wait before prefetch when paging.
chunk.size.message.read	Optional. Defaults to 100. Controls the number of messages to be retrieved in parallel.
mailbox.blob.part.size	Optional. Defaults to 102400 (100KB). Controls the size of blob parts used to store messages in the Cassandra blobStore.
mailbox.read.strong.consistency	Optional. Boolean, defaults to true. Disabling should be considered experimental. If enabled, regular consistency level is used for read transactions for mailbox. Not doing so might result in stale reads as the system.paxos table will not be checked for latest updates. Better performance are expected by turning it off. Note that reads performed as part of write transactions are always performed with a strong consistency.
message.read.strong.consistency	Optional. Boolean, defaults to true. Disabling should be considered experimental. If enabled, regular consistency level is used for read transactions for message. Not doing so might result in stale reads as the system.paxos table will not be checked for latest updates. Better performance are expected by turning it off. Note that reads performed as part of write transactions are always performed with a strong consistency.
message.write.strong.consistency.unsafe	Optional. Boolean, defaults to true. Disabling should be considered experimental and unsafe. If disabled, Lightweight transactions will no longer be used upon messages operation (table `imapUidTable`). As message flags updates relies so far on a read-before-write model, it exposes yourself to data races leading to potentially update loss. Better performance are expected by turning it off. Reads performed as part of write transaction are also performed with a relaxed consistency.