listShards¶

Definition定义¶

listShards¶

The listShards command returns a list of the configured shards in a sharded cluster. listShards is only available on mongos instances and must be issued against the admin database.

The command takes the following form:

{ listShards: 1 }

Example示例¶

The following operation runs listShards against the mongos admin database:

db.adminCommand({ listShards: 1 })

The following document is an example of the output from a listShards command:

{
  "shards": [
    {
      "_id": "shard01",
      "host": "shard01/host1:27018,host2:27018,host3:27018",
      "state": 1
    },
    {
      "_id": "shard02",
      "host": "shard02/host4:27018,host5:27018,host6:27018",
      "tags": [ "NYC" ],
      "state": 1
    },
    {
      "_id": "shard03",
      "host": "shard03/host7:27018,host8:27018,host9:27018",
      "maxSize": NumberLong("1024"),
      "state": 1
    }
  ],
  "ok": 1,
  "$clusterTime" : {
     "clusterTime" : Timestamp(1510716515, 1),
     "signature" : {
        "hash" : BinData(0,"B2ViX7XLzFLS5Fl9XEuFXbwKIM4="),
        "keyId" : NumberLong("6488045157173166092")
     }
  },
  "operationTime" : Timestamp(1510716515, 1)
}

Output¶

listShards returns a document that includes:

• A shards field which contains an array of documents, each describing one shard. Each document may contain the following fields:

  Field字段	Description描述
  _id	The name of the shard.
  host	The hostname of the shard. If the shard is a replica set, host lists the hostname of each mongod instance in the replica set.
  draining	If true, indicates that removeShard has been called for this shard and it is in the process of being drained.
  tags	A list of zones to which the shard belongs.
  maxSize	The configured maximum storage size of the shard in megabytes. This includes all data files on the shard including the local and admin databases. If exceeded, this shard will not receive any more chunks.
  state	An internal field used during the addShard sequence to ensure that all steps and configuration necessary to add the shard to the cluster are completed.

• The ok status field, the operationTime field, and the $clusterTime field for the operation. For details on these fields, see Response.