3.3. Configuring Clustering¶

3.3.1. Cluster Options¶

[cluster]¶

q¶

Sets the default number of shards for newly created databases. The default value, 8, splits a database into 8 separate partitions.

[cluster]
q = 8

For systems with lots of small, infrequently accessed databases, or for servers with fewer CPU cores, consider reducing this value to 1 or 2.

The value of q can also be overridden on a per-DB basis, at DB creation time.

See also

PUT /{db}

n¶

Sets the number of replicas of each document in a cluster. CouchDB will only place one replica per node in a cluster. When set up through the Cluster Setup Wizard, a standalone single node will have n = 1, a two node cluster will have n = 2, and any larger cluster will have n = 3. It is recommended not to set n greater than 3.

[cluster]
n = 3

placement¶

Warning

Use of this option will override the n option for replica cardinality. Use with care.

Sets the cluster-wide replica placement policy when creating new databases. The value must be a comma-delimited list of strings of the format zone_name:#, where zone_name is a zone as specified in the nodes database and # is an integer indicating the number of replicas to place on nodes with a matching zone_name.

This parameter is not specified by default.

[cluster]
placement = metro-dc-a:2,metro-dc-b:1