balancerStart
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Definition
balancerStart
Starts the balancer thread. The command does not wait for a balancing round to start.
Tip
In
mongosh
, this command can also be run through thesh.startBalancer()
helper method.Helper methods are convenient for
mongosh
users, but they may not return the same level of information as database commands. In cases where the convenience is not needed or the additional return fields are required, use the database command.Starting in MongoDB 6.1, automatic chunk splitting is not performed. This is because of balancing policy improvements. Auto-splitting commands still exist, but do not perform an operation. For details, see Balancing Policy Changes.
In MongoDB versions earlier than 6.1, the command enables auto-splitting for the sharded cluster. To disable auto-splitting when the balancer is enabled, you can use
sh.disableAutoSplit()
.
Syntax
You can only issue the
balancerStart
against the admin
database on a
mongos
instance.
The command has the following syntax:
db.adminCommand( { balancerStart: 1, maxTimeMS: <number> } )
Command Fields
Field | Type | Description |
---|---|---|
balancerStart | any | Any value. |
maxTimeMS | integer | Optional. Time limit for enabling the balancer. Defaults to 60000 milliseconds. |
Example
To start the balancer thread, connect to a mongos
instance
and issue the following command:
db.adminCommand( { balancerStart: 1 } )