Attribute

WriteConsistency (WC)

Purpose

Determines the number of replicas on which the write must succeed before returning an acknowledgment to the client application.

Valid Values

0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10

Behavior

If set to 0 (any), a write must succeed on at least one node. Even if all replica nodes for the given partition key are down, the write can succeed after a hinted handoff has been written. This setting provides the lowest consistency and highest availability.

If set to 1 (one), a write must succeed on at least one replica node.

If set to 2 (two), a write must succeed on at least two replica nodes.

If set to 3 (three), a write must succeed on at least three replica nodes.

If set to 4 (quorum), a write must succeed on a quorum of replica nodes.

If set to 5 (all), a write must succeed on all replica nodes in the cluster for that partition key. This setting provides the highest consistency and lowest availability.

If set to 6 (local_quorum), a write must succeed on a quorum of replica nodes in the same data center as the coordinator node. This setting avoids latency of inter-data center communication.

If set to 7 (each_quorum), a write must succeed on a quorum of replica nodes across a data center.

(Cassandra 2.x only) If set to 8 (serial), the driver prevents unconditional updates to achieve linearizable consistency for lightweight transactions.

(Cassandra 2.x only) If set to 9 (local_serial), the driver prevents unconditional updates to achieve linearizable consistency for lightweight transactions within the data center.

If set to 10 (local_one), a write must succeed on at least one replica node in the local data center.

Notes

  • An update operation can result in a consistency level error if the server does not support the WriteConsistency value specified.
  • Refer to Apache Cassandra documentation for more information about configuring consistency levels, including usage scenarios.

Default

4 (quorum)

GUI Tab

Advanced tab