Specifies ZooKeeper session timeout, in milliseconds. The default value is 30000 ms.

If the server fails to signal heartbeat to ZooKeeper within this period of time, the server is considered to be dead. If you set this value too low, the server might be falsely considered dead; if you set it too high it may take too long to recognize a truly dead server.

If you see frequent disconnection from the ZooKeeper server, review this setting. If long garbage collection pauses cause Kafka to lose its ZooKeeper session, you might need to configure longer timeout values.

If you have manually set listeners to advertised.listeners=PLAINTEXT://$HOSTNAME:$PORT, after enabling Kerberos, change the listener configuration to advertised.listeners= SASL_PLAINTEXT://$HOSTNAME:$PORT.

Enable automatic creation of topics on the server. If this property is set to true, then attempts to produce, consume, or fetch metadata for a nonexistent topic automatically create the topic with the default replication factor and number of partitions. The default is enabled.

Specifies default replication factors for automatically created topics. For high availability production systems, you should set this value to at least 3.

Specifies the default number of log partitions per topic, for automatically created topics. The default value is 1. Change this setting based on the requirements related to your topic and partition design.

Allows users to delete a topic from Kafka using the admin tool, for Kafka versions 0.9 and later. Deleting a topic through the admin tool will have no effect if this setting is turned off.

By default this feature is turned off (set to false).

The maximum time, in hours, before a new log segment is rolled out. The default value is 168 hours (seven days).

This setting controls the period of time after which Kafka will force the log to roll, even if the segment file is not full. This ensures that the retention process is able to delete or compact old data.

The number of hours to keep a log file before deleting it. The default value is 168 hours (seven days).

When setting this value, take into account your disk space and how long you would like messages to be available. An active consumer can read quickly and deliver messages to their destination.

The higher the retention setting, the longer the data will be preserved. Higher settings generate larger log files, so increasing this setting might reduce your overall storage capacity.

A comma-separated list of directories in which log data is kept. If you have multiple disks, list all directories under each disk.

The amount of data to retain in the log for each topic partition. By default, log size is unlimited.

Note that this is the limit for each partition, so multiply this value by the number of partitions to calculate the total data retained for the topic.

If log.retention.hours and log.retention.bytes are both set, Kafka deletes a segment when either limit is exceeded.

The log for a topic partition is stored as a directory of segment files. This setting controls the maximum size of a segment file before a new segment is rolled over in the log. The default is 1 GB.

Specifies total memory used for log deduplication across all cleaner threads.

By default, 128 MB of buffer is allocated. You may want to review this and other log.cleaner configuration values, and adjust settings based on your use of compacted topics (__consumer_offsets and other compacted topics).

Specifies the total memory used for log cleaner I/O buffers across all cleaner threads. By default, 512 KB of buffer is allocated. You may want to review this and other log.cleaner configuration values, and adjust settings based on your usage of compacted topics (__consumer_offsets and other compacted topics).

Enables automatic leader balancing. A background thread checks and triggers leader balancing (if needed) at regular intervals. The default is enabled.

This property allows you to specify a preference of availability or durability. This is an important setting: If availability is more important than avoiding data loss, ensure that this property is set to true. If preventing data loss is more important than availability, set this property to false.

This setting operates as follows:

This property is set to true by default, which favors availability.

If durability is preferable to availability, set unclean.leader.election to false.

Enables controlled shutdown of the server. The default is enabled.

When a producer sets acks to "all", min.insync.replicas specifies the minimum number of replicas that must acknowledge a write for the write to be considered successful. If this minimum cannot be met, then the producer will raise an exception.

When used together, min.insync.replicas and producer acks allow you to enforce stronger durability guarantees.

You should set min.insync.replicas to 2 for replication factor equal to 3.

Specifies the maximum size of message that the server can receive. It is important that this property be set with consideration for the maximum fetch size used by your consumers, or a producer could publish messages too large for consumers to consume.

Note that there are currently two versions of consumer and producer APIs. The value of message.max.bytes must be smaller than the max.partition.fetch.bytes setting in the new consumer, or smaller than the fetch.message.max.bytes setting in the old consumer. In addition, the value must be smaller than replica.fetch.max.bytes.

Specifies the number of bytes of messages to attempt to fetch. This value must be larger than message.max.bytes.

The rack awareness feature distributes replicas of a partition across different racks. You can specify that a broker belongs to a particular rack through the "Custom kafka-broker" menu option. For more information about the rack awareness feature, see http://kafka.apache.org/documentation.html#basic_ops_racks.