Details
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Bug
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Resolution: Won't Do
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Major - P3
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None
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MDB 3.0.3, Pymongo 2.8, AWS Linux
*Location*: http://docs.mongodb.org/manual/tutorial/split-chunks-in-sharded-cluster/
*User-Agent*: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.81 Safari/537.36
*Referrer*: http://docs.mongodb.org/manual/administration/sharded-cluster-data/
*Screen Resolution*: 1440 x 900
*repo*: docs
*source*: tutorial/split-chunks-in-sharded-cluster
MDB 3.0.3, Pymongo 2.8, AWS Linux *Location*: http://docs.mongodb.org/manual/tutorial/split-chunks-in-sharded-cluster/ *User-Agent*: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.81 Safari/537.36 *Referrer*: http://docs.mongodb.org/manual/administration/sharded-cluster-data/ *Screen Resolution*: 1440 x 900 *repo*: docs *source*: tutorial/split-chunks-in-sharded-cluster
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0.25
Description
This statement is extremely hopeful as I contemplate converting a big replica set into a sharded DB:
"When you shard a collection that has existing data, MongoDB automatically creates chunks to evenly distribute the collection"
However, it doesn't give me any idea how it does this. So I'm not sure how confident I should be with its technique.
The only things I've found that seem relevant to my challenge suggest somewhat involved approaches to pre-splitting data (http://stackoverflow.com/questions/19672302/how-to-programatically-pre-split-a-guid-based-shard-key-with-mongodb). If the above statement is telling me what I hope it is then my strategy would be to create a new sharded cluster in which my original replica set is one shard. Then I would drain that shard. But that goes against what this page says:
http://docs.mongodb.org/manual/tutorial/remove-shards-from-cluster/
"This procedure describes how to safely remove a single shard. Do not use this procedure to migrate an entire cluster to new hardware."
Now, I think I understand the intent there. But there's room for different interpretations.
This is close:
http://docs.mongodb.org/manual/tutorial/convert-replica-set-to-replicated-shard-cluster/
But again, it isn't a complete statement.