how to split the chunks in sharding

Question

I have edited the question. I was trying to run the sh.splitAt

mongos> sh.splitAt("test.zp",{"city": "1"})it worked.

But the problem is at sharding chunks.

when i have run the command sh.status(). It shows like this

databases:
{  "_id" : "admin",  "partitioned" : false,  "primary" : "config" }
{  "_id" : "test",  "partitioned" : true,  "primary" : "shard0000" }
test.zp
shard key: { "city" : 1 }
chunks:shard0000  34
too many chunks to print, use verbose if you want to force print.

i have three more shards but with different ip's.why sharding is not applied to the secondary shards. I have shards like

    {  "_id" : "shard0000", }  
{  "_id" : "shard0001", } 
{  "_id" : "shard0002", }  
{  "_id" : "shard0003", }

How chunks will be added to "shard0001" and remaining shards.I have added all shards to the test db. and my data is 1.2GB.

Answer 1

You need to enable sharding on the database test first:

sh.enableSharding("test");

Then you need to shard the collection and pick a shard key. Based on what you were trying to split on, that would be:

sh.shardCollection("test.zp", {"city" : 1});

A couple of notes:

1. "city" is probably a poor shard key unless you are expecting an even distribution of records per city and you are going to have a lot of them. Take a look at the docs on picking a key
2. If you have data in the collection already, you will need to create an index on the "city" field before you can use it as a shard key. If the collection is empty, MongoDB will do it for you automatically when you use it as a shard key.