sh.addShardToZone()
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Definition
sh.addShardToZone(shard, zone)
New in version 3.4: 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.
Important
mongo Shell Method
This page documents a
mongo
method. This is not the documentation for database commands or language-specific drivers, such as Node.js. To use the database command, see theaddShardToZone
command.For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.
This method has the following parameter:
ParameterTypeDescriptionstringThe name of the shard to which to associate the zone.
stringThe name of the zone to associate with the shard.
Only issue
sh.addShardToZone()
when connected to amongos
instance.
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 sharded clusters.
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
sh.updateZoneKeyRange()
method.
Starting in MongoDB 4.0.2, you can run
updateZoneKeyRange
database command and its helpers
sh.updateZoneKeyRange()
and sh.addTagRange()
on
an unsharded collection or a non-existing collection.
Tip
By defining the zones and the zone ranges before sharding an empty or a non-existing collection, the shard collection operation creates chunks for the defined zone ranges as well as any additional chunks to cover the entire range of the shard key values and performs an initial chunk distribution based on the zone ranges. This initial creation and distribution of chunks allows for faster setup of zoned sharding. After the initial distribution, the balancer manages the chunk distribution going forward.
See Pre-Define Zones and Zone Ranges for an Empty or Non-Existing Collection for an example.
Security
For sharded clusters that enforce access control, you must authenticate as a user whose privileges include either:
update
on theshards
collection in theconfig
database; or, alternatively,enableSharding
on the cluster resource (Starting in version 4.2.2).
The clusterAdmin
or clusterManager
built-in roles have
the appropriate permissions for issuing sh.addShardToZone()
. See the
Role-Based Access Control manual page for more
information.
Example
The following example adds three zones, NYC
, LAX
, and NRT
,
associating each to a shard:
sh.addShardToZone("shard0000", "JFK") sh.addShardToZone("shard0001", "LAX") sh.addShardToZone("shard0002", "NRT")
A shard can associate with multiple zones. The following example associates
LGA
to shard0000
:
sh.addShardToZone("shard0000", "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
.