2. Update the _waitForDelete value in the settings (page 741) collection of the config database (page 737). For example: 

use config db.settings.update( { "_id" : "balancer" }, { $set : { "_waitForDelete" : true } }, { upsert : true } ) 

Once set to true , to revert to the default behavior: 

1. Connect to a mongos instance. 

2. Update or unset the _waitForDelete field in the settings (page 741) collection of the config database (page 737): 

use config db.settings.update( { "_id" : "balancer", "_waitForDelete": true }, { $unset : { "_waitForDelete" : "" } } ) 

## Manage Sharded Cluster Balancer 

This page describes common administrative procedures related to balancing. For an introduction to balancing, see Sharded Collection Balancing (page 684). For lower level information on balancing, see Cluster Balancer (page 684). 

## See also: 

Configure Behavior of Balancer Process in Sharded Clusters (page 713) 

## Check the Balancer State 

The following command checks if the balancer is enabled (i.e. that the balancer is allowed to run). The command does not check if the balancer is active (i.e. if it is actively balancing chunks). 

To see if the balancer is enabled in your cluster , issue the following command, which returns a boolean: 

sh.getBalancerState() 

New in version 3.0.0: You can also see if the balancer is enabled using sh.status() . The currently-enabled field indicates whether the balancer is enabled, while the currently-running field indicates if the balancer is currently running. 

## Check the Balancer Lock 

To see if the balancer process is active in your cluster , do the following: 

1. Connect to any mongos in the cluster using the mongo shell. 

2. Issue the following command to switch to the Config Database (page 737): 

use config 

3. Use the following query to return the balancer lock: 

