addShardToZone¶

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Definition
Behavior
Security
Example

Definition¶

addShardToZone¶

3.4 新版功能: Associates a shard with a zone. MongoDB associates this shard with the given zone. Chunks that are covered by the zone are assigned to shards associated with the zone.

To run addShardToZone, use the db.runCommand( { <command> } ) method.

You must run addShardToZone on the admin database.

The addShardToZone command has the following syntax:

{
  addShardToZone: <string>,
  zone: <string>
}

The command takes the following fields:

Field	Type	Description
`addShardtoZone`	string	The name of the shard to associate with the `zone`.
`zone`	string	The name of the zone to associate with the `shard`.

Only issue addShardToZone when connected to a mongos instance.

The mongo shell provides the helper method sh.addShardToZone()

Behavior¶

You can associate a zone with multiple shards, and a shard can associate with multiple zones.

See the zone manual page for more information on zones in a sharded cluster.

Ranges¶

MongoDB effectively ignores zones that do not have at least one range of shard key values associated with it.

To associate a range of shard key values with a zone, use the updateZoneKeyRange database command, or the sh.updateZoneKeyRange() shell helper.

Security¶

For sharded clusters running with authentication, you must authenticate as a user whose privileges include update on the config.shards collection or the config database.

The clusterAdmin or clusterManager built-in roles have the appropriate permissions for issuing addShardToZone. See the documentation page for Role-Based Access Control for more information.

Example¶

The following example associates shard0000 with zone JFK:

admin = db.getSiblingDB("admin")
admin.runCommand( { addShardToZone : "shard0000" , zone : "JFK" } )

A shard can associate with multiple zones. The following example associates LGA to shard0000:

admin = db.getSiblingDB("admin")
admin.runCommand( { addShardToZone : "shard0000" , zone : "LGA" } )

shard0000 associates with both the LGA zone and the JFK zone. In a balanced cluster, MongoDB routes reads and writes covered by either zone to shard0000.

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