4.3. Configuring Clustering — Apache CouchDB 2.3 Documentation

# 4.3. Configuring Clustering

## 4.3.1. 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

  httpdomain:put:PUT /{db} </{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`

  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

  See also

  Placing a database on specific nodes

  `seedlist`

  An optional, comma-delimited list of node names that this node should contact in order to join a cluster. If a seedlist is configured the `_up` endpoint will return a 404 until the node has successfully contacted at least one of the members of the seedlist and replicated an up-to-date copy of the `_nodes`, `_dbs`, and `_users` system databases.

  > [cluster] seedlist = couchdb@node1.example.com,couchdb@node2.example.com