Configuring the replication factor
Ensure reliability and fault tolerance by controlling how many data replicas you want to store across a Cassandra cluster.
The replication factor is the total number of replicas for a keyspace across a Cassandra cluster. A replication factor of 3 means that there are three copies of each row, where each copy is on a different node and is equally important.
By setting a high replication factor, you ensure a higher likelihood that the data on the node exists on another node, in case of a failure. The disadvantage of a high replication factor is that write operations take longer.
To change the default replication factor, open the
prconfig.xmlfile and modify the dnode/default_keyspaces property.The default setting for all keyspaces is 3:
- Impact of failing nodes on system stability
Learn how the number of functional nodes and the current replication factor affect system stability when some of the Cassandra nodes are down.
- Configuring the consistency level
Achieve the level of consistency that you want by deciding how many Cassandra nodes in a cluster must validate a write operation or respond to a read operation to declare success.
- Verifying the keyspace replication factor
Troubleshoot keyspace-related errors, such as incorrect replication, by checking whether a specific keyspace exists and whether the keyspace belongs to the correct data center.