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- movePrimary
movePrimary¶
-
movePrimary
¶ In a sharded cluster, this command reassigns the database’s primary shard, which holds all un-sharded collections in the database.
movePrimary
is an administrative command that is only available formongos
instances. Only usemovePrimary
when removing a shard from a sharded cluster.Important
Only use
movePrimary
when:- the database does not contain any collections with data, or
- you have drained all sharded collections using the
removeShard
command.
See Remove Shards from an Existing Sharded Cluster for a complete procedure.
movePrimary
changes the primary shard for this database in the cluster metadata, and migrates all un-sharded collections to the specified shard. Use the command with the following form:When the command returns, the database’s primary location will shift to the designated shard. To fully decommission a shard, use the
removeShard
command.