balancerStatus

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Definition

Compatibility
Syntax
Output Document
Example

Definition

balancerStatus

New in version 3.4.

Returns a document that contains information about the status of the balancer.

You can only issue the balancerStatus against the admin database.

Tip

In mongosh, this command can also be run through the sh.isBalancerRunning() 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.

Compatibility

This command is available in deployments hosted in the following environments:

MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

Important

This command is not supported in serverless instances. For more information, see Unsupported Commands.

MongoDB Enterprise: The subscription-based, self-managed version of MongoDB
MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB

Syntax

The command has the following syntax:

db.adminCommand( { balancerStatus: 1 } )

Output Document

The following is an example of a document returned by the command:

{
   "mode" : "full",
   "inBalancerRound" : false,
   "numBalancerRounds" : NumberLong(86),
   "ok" : 1
}

Field	Description
`"mode"`	A string that specifies whether the balancer thread is running or stopped. Possible values are: "full" Balancer thread is running but not necessarily in a balancing round. "off" Balancer thread is stopped. No chunk balancing can occur in this mode.
`"inBalancerRound"`	A boolean that specifies if the balancer is in a balancing round. If `inBalancerRound=true`, it is now distributing chunks. `inBalancerRound` can be `true` when `mode=off`. If you turn the balancer off while it's in a balancing round, the server lets it finish rather than interrupting it.
`"numBalancerRounds"`	The number of balancer rounds which have occurred since the config servers were started. This value is not persisted and is reset to 0 upon restart of the config servers.

Example

Connect to a mongos instance and issue the following command:

db.adminCommand( { balancerStatus: 1 } )

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balancerStart

balancerStop