sh.enableSharding()¶

On this page

Definition
Syntax
Behavior
Example

Definition¶

sh.enableSharding(database, primaryShard)¶: Enables sharding on the specified database. Once you enabled sharding for a database, you can use sh.shardCollection() to shard collections in that database. The mongo shell method sh.enableSharding() wraps the enableSharding command.

Syntax¶

The sh.enableSharding has the following form:

sh.enableSharding(
   <database>,
   <primary shard>  // Optional. Available starting in MongoDB 4.2.2 (and 4.0.14)
)

Parameter¶

The sh.enableSharding() method takes the following parameter:

Parameter

Type

Description

database

String

The database for which you wish to enable sharding.

primaryShard

String

Optional. The primary shard for the database; the primary shard contains the unsharded collection for this database. In general, rather than explicitly specifying the primary shard, it is recommended to let the balancer select the primary shard instead.

Tip

In general, you should not need to specify the primary shard. Allow the balancer to select the primary shard instead.

Available starting in MongoDB 4.2.2 (and 4.0.14)

Behavior¶

Write Concern¶

mongos uses "majority" for the enableSharding command and its helper sh.enableSharding().

Primary Shard¶

In general, you should not need to specify the primaryShard in the command. Instead, allow the balancer to select the primary shard.

However, if you do specify the primary shard for a database and the database is already enabled for sharding with a different primary shard, the operation returns an error and the primary shard for the database remains as before. To change the primary shard for a database, use the movePrimary command instead.

Example¶

The following example, run from a mongos, enables sharding for the test database:

copy

sh.enableSharding("test")

To verify, run sh.status().