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Enables the autosplit flag in the
config.settingscollection. When auto-splitting is enabled for a sharded cluster, MongoDB automatically splits chunks based on the shard key values the chunk represents to keep the chunks from growing too large.
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,
sh.startBalancer()also enables auto-splitting for the sharded cluster.