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Add Shards to a Cluster将分片添加到集群

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You add shards to a sharded cluster after you create the cluster or any time that you need to add capacity to the cluster. 在创建集群后，或者在需要向集群添加容量的任何时候，将分片添加到分片集群中。If you have not created a sharded cluster, see Deploy a Sharded Cluster.如果尚未创建分片集群，请参阅部署分片集群。

In production environments, all shards should be replica sets.在生产环境中，所有分片都应该是副本集。

Considerations注意事项

Balancing平衡

When you add a shard to a sharded cluster, you affect the balance of chunks among the shards of a cluster for all existing sharded collections. 将分片添加到分片集群时，会影响所有现有分片集合的集群分片之间的块平衡。The balancer will begin migrating chunks so that the cluster will achieve balance. 平衡器将开始迁移块，以便集群实现平衡。See Balancer Internals for more information.有关更多信息，请参阅平衡器内部。

Capacity Planning产能规划

When adding a shard to a cluster, always ensure that the cluster has enough capacity to support the migration required for balancing the cluster without affecting legitimate production traffic.在向集群添加分片时，始终确保集群有足够的容量来支持平衡集群所需的迁移，而不会影响合法的生产流量。

Add a Shard to a Cluster将分片添加到群集

You interact with a sharded cluster by connecting to a mongos instance.您可以通过连接到mongos实例来与分片集群进行交互。

  1. In mongosh, connect to the mongos instance. 在mongosh中，连接到mongos实例。For example, if a mongos is accessible at mongos0.example.net on port 27017, issue the following command:例如，如果可以在mongos0.example.net的端口27017上访问mongos，请发出以下命令：

    mongosh --host mongos0.example.net --port 27017
  2. Add a shard to the cluster using the sh.addShard() method, as shown in the examples below. 使用sh.addShard()方法将分片添加到集群中，如下例所示。Issue sh.addShard() separately for each shard. 为每个分片分别发出sh.addShard()。If the shard is a replica set, specify the name of the replica set and specify a member of the set. 如果分片是副本集，请指定副本集的名称并指定该集的成员。In production deployments, all shards should be replica sets.在生产部署中，所有分片都应该是副本集。

    Note

    Optional可选择的

    You can instead use the addShard database command, which lets you specify a name and maximum size for the shard. 您可以使用addShard数据库命令，该命令允许您指定分片的名称和最大大小。If you do not specify these, MongoDB automatically assigns a name and maximum size.如果您没有指定这些，MongoDB会自动分配一个名称和最大大小。 To use the database command, see addShard.要使用数据库命令，请参阅addShard。

    The following are examples of adding a shard with sh.addShard():以下是使用sh.addShard()添加分片的示例：

    • To add a replica set shard named rs1 with a member running on port 27018 on mongodb0.example.net, issue the following command:要添加名为rs1的副本集分片，其成员运行在mongodb0.example.net的27018端口上，请发出以下命令：

      sh.addShard( "rs1/mongodb0.example.net:27018" )
    • To add a standalone mongod shard running on port 27018 of mongodb0.example.net, issue the following command:要添加在mongodb0.example.net的27018端口上运行的独立mongod分片，请发出以下命令：

      sh.addShard( "mongodb0.example.net:27018" )
    Note

    It might take some time for chunks to migrate to the new shard.块迁移到新的分片可能需要一些时间。