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- sh.addShard()
sh.addShard()¶
On this page
Definition¶
-
sh.
addShard
(<url>)¶ Adds a shard replica set to a sharded cluster. This method must be run on a
mongos
instance.Important
mongo
Shell MethodThis 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 theaddShard
command.For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.
The
sh.addShard()
method has the following parameter:Parameter Type Description host
string The replica set name, hostname, and port of at least one member of the shard’s replica set. Any additional replica set member hostnames must be comma separated. For example:
The
sh.addShard()
method has the following prototype form:Warning
Do not use
localhost
for the hostname unless your config server is also running onlocalhost
.mongos
installed from official .deb and .rpm packages have thebind_ip
configuration set to127.0.0.1
by default.mongos
uses"majority"
for theaddShard
command and its helpersh.addShard()
.
Considerations¶
Balancing¶
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. The balancer will begin migrating chunks so that the cluster will achieve balance. See Cluster Balancer for more information.
Chunk migrations can have an impact on disk space, as the source shard automatically archives the migrated documents by default. For details, see moveChunk directory.
Example¶
To add a shard, specify the name of the replica set and the hostname of at least one member of the replica set, as a seed. If you specify additional hostnames, all must be members of the same replica set.
The following example adds a replica set named repl0
and specifies
one member of the replica set: