Database Manual / Reference / Database Commands / Sharding

getShardMap (database command)

getShardMap

getShardMap returns the following information about your cluster:

  • The names of your shards and the config server replica set
  • Hostnames and connection strings for the nodes that comprise the cluster's shards and the config server replica set

You must use the admin database to run getShardMap.

Compatibility

This command is available in deployments hosted in the following environments:

  • MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

Important

This command is not supported in M0 and Flex clusters. For more information, see Unsupported Commands.

Syntax

The command has the following syntax:

db.runCommand("getShardMap")

Output Document

Here's an example of the output the command returns:

{
  map: {
    shard01: 'shard01/localhost:27018,localhost:27019,localhost:27020,localhost:27021,localhost:27022',
    shard02: 'shard02/localhost:27023,localhost:27024,localhost:27025,localhost:27026,localhost:27027',
    shard03: 'shard03/localhost:27028,localhost:27029,localhost:27030,localhost:27031,localhost:27032',
    config: 'configRepl/localhost:27033',localhost:27034,localhost:27035,localhost:27036,localhost:27037'
  },
  hosts: {
    'localhost:27021': 'shard01',
    'localhost:27022': 'shard01',
    'localhost:27028': 'shard03',
    'localhost:27026': 'shard02',
    'localhost:27020': 'shard01',
    'localhost:27032': 'shard03',
    'localhost:27027': 'shard02',
    'localhost:27024': 'shard02',
    'localhost:27018': 'shard01',
    'localhost:27019': 'shard01',
    'localhost:27031': 'shard03',
    'localhost:27025': 'shard02',
    'localhost:27029': 'shard03',
    'localhost:27023': 'shard02',
    'localhost:27030': 'shard03',
    'localhost:27033': 'config'
    'localhost:27036': 'config'
    'localhost:27034': 'config'
    'localhost:27037': 'config'
    'localhost:27035': 'config'
  },
  connStrings: {
    'shard01/localhost:27018,localhost:27019,localhost:27020,localhost:27021,localhost:27022': 'shard01',
    'shard01/localhost:27019,localhost:27020,localhost:27021': 'shard01',
    'shard01/localhost:27020,localhost:27021': 'shard01',
    'shard01/localhost:27021': 'shard01',
    'shard02/localhost:27023,localhost:27024,localhost:27025,localhost:27026,localhost:27027': 'shard02',
    'shard02/localhost:27025,localhost:27026,localhost:27027': 'shard02',
    'shard02/localhost:27025,localhost:27027': 'shard02',
    'shard03/localhost:27028,localhost:27029,localhost:27030,localhost:27031,localhost:27032': 'shard03',
    'shard03/localhost:27032': 'shard03',
    'configRepl/localhost:27033',localhost:27036,localhost:27034,localhost:27037,localhost:27035': 'config'
  },
  ok: 1
}

The command returns the following fields:

FieldDescription

"map"

List of shards in the cluster, the config server for the cluster, and the hostname and port for every node in the cluster.

"hosts"

List of hostnames and ports for the nodes of the cluster and the shards or config server to which they map.

"connStrings"

List of connection strings for the nodes grouped by the shard or config server the node belongs to.

Learn More

For more sharding commands, see Sharding Commands.