使用MongoDB进行分片

Question

I am newbie to MongoDB Sharding. I have created mongos and config server and one shard on xyz.com , and second shard on xyzshard.com server:

• mongos on xyz.com:27019

• config server on xyz.com:27018

• 1st shard on xyz.com:27017

• 2nd shard on xyzshard.com:27017

My database is test and collection is test_collection . I have enabled sharding on test.test_collection .

I have indexed _id field using "hash"

db.test_collection.ensureIndex( { _id : "hashed" } )

I run the following command:

for (var i = 1; i <= 500; i++) 
    db.test_collection.insert( { x : i } )

I get the output below:

WriteResult({ "nInserted" : 1 })

But when I run find query on both shards like this:

db.test_collection.find()

I get all documents on each shard.

Is it the right way or I am going wrong anywhere?

Output for sh.status() on xyz.com is

sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("55b8d3e9a8742d49164820b6")
}
  shards:
    {  "_id" : "shard0000",  "host" : "localhost:27017" }
  balancer:
    Currently enabled:  yes
    Currently running:  no
    Failed balancer rounds in last 5 attempts:  0
    Migration Results for the last 24 hours: 
        No recent migrations
  databases:
    {  "_id" : "admin",  "partitioned" : false,  "primary" : "config" }
    {  "_id" : "test",  "partitioned" : true,  "primary" : "shard0000" }
        test.test_collection
            shard key: { "_id" : "hashed" }
            chunks:
                shard0000   2
            { "_id" : { "$minKey" : 1 } } -->> { "_id" : NumberLong(0) } on : shard0000 Timestamp(1, 1) 
            { "_id" : NumberLong(0) } -->> { "_id" : { "$maxKey" : 1 } } on : shard0000 Timestamp(1, 2) 
    {  "_id" : "test_db",  "partitioned" : false,  "primary" : "shard0000" }
    {  "_id" : "db",  "partitioned" : false,  "primary" : "shard0000" } 

Output for sh.status() on xyzshard.com

sharding version: {
    "_id" : 1,
    "minCompatibleVersion" : 5,
    "currentVersion" : 6,
    "clusterId" : ObjectId("55b8d3e9a8742d49164820b6")
}
  shards:
    {  "_id" : "shard0000",  "host" : "localhost:27017" }
  databases:
    {  "_id" : "admin",  "partitioned" : false,  "primary" : "config" }
    {  "_id" : "test",  "partitioned" : true,  "primary" : "shard0000" }
        test.test_collection
            shard key: { "_id" : "hashed" }
            chunks:
                shard0000   2
            { "_id" : { "$minKey" : 1 } } -->> { "_id" : NumberLong(0) } on : shard0000 Timestamp(1, 1) 
            { "_id" : NumberLong(0) } -->> { "_id" : { "$maxKey" : 1 } } on : shard0000 Timestamp(1, 2) 
    {  "_id" : "test_db",  "partitioned" : false,  "primary" : "shard0000" }
    {  "_id" : "db",  "partitioned" : false,  "primary" : "shard0000" }

Answer 1

You should connect to your mongos server and insert data on it.You could insert 50000 records for testing purpose. And after that run sh.status().

You would finally see the distribution. Remember your config server should be running and all the shard servers are connected to the mongos server.