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View Cluster Configuration¶
List Databases with Sharding Enabled¶
To list the databases that have sharding enabled, query the databases collection in the Config Database. A database has sharding enabled if the value of the partitioned field is true. Connect to a mongos instance with a mongo shell, and run the following operation to get a full list of databases with sharding enabled:
use config
db.databases.find( { "partitioned": true } )
Example
You can use the following sequence of commands when to return a list of all databases in the cluster:
use config
db.databases.find()
If this returns the following result set:
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "animals", "partitioned" : true, "primary" : "m0.example.net:30001" }
{ "_id" : "farms", "partitioned" : false, "primary" : "m1.example2.net:27017" }
Then sharding is only enabled for the animals database.
List Shards¶
To list the current set of configured shards, use the listShards command, as follows:
use admin
db.runCommand( { listShards : 1 } )
View Cluster Details¶
To view cluster details, issue db.printShardingStatus() or sh.status(). Both methods return the same output.
Example
In the following example output from sh.status()
- sharding version displays the version number of the shard metadata.
- shards displays a list of the mongod instances used as shards in the cluster.
- databases displays all databases in the cluster, including database that do not have sharding enabled.
- The chunks information for the foo database displays how many chunks are on each shard and displays the range of each chunk.
--- Sharding Status ---
sharding version: { "_id" : 1, "version" : 3 }
shards:
{ "_id" : "shard0000", "host" : "m0.example.net:30001" }
{ "_id" : "shard0001", "host" : "m3.example2.net:50000" }
databases:
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "contacts", "partitioned" : true, "primary" : "shard0000" }
foo.contacts
shard key: { "zip" : 1 }
chunks:
shard0001 2
shard0002 3
shard0000 2
{ "zip" : { "$minKey" : 1 } } -->> { "zip" : "56000" } on : shard0001 { "t" : 2, "i" : 0 }
{ "zip" : 56000 } -->> { "zip" : "56800" } on : shard0002 { "t" : 3, "i" : 4 }
{ "zip" : 56800 } -->> { "zip" : "57088" } on : shard0002 { "t" : 4, "i" : 2 }
{ "zip" : 57088 } -->> { "zip" : "57500" } on : shard0002 { "t" : 4, "i" : 3 }
{ "zip" : 57500 } -->> { "zip" : "58140" } on : shard0001 { "t" : 4, "i" : 0 }
{ "zip" : 58140 } -->> { "zip" : "59000" } on : shard0000 { "t" : 4, "i" : 1 }
{ "zip" : 59000 } -->> { "zip" : { "$maxKey" : 1 } } on : shard0000 { "t" : 3, "i" : 3 }
{ "_id" : "test", "partitioned" : false, "primary" : "shard0000" }
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