setting up mongodb for sharding/scalability?

Any recommended readings for setting up mongodb for sharding/scalability?

I'm looking for best practices. i don't know a lot about sharding or scaling db solutions. are there examples out there with practical real world examples?

i apologi开发者_StackOverflow社区ze if i'm using the wrong terms.

1. Is my understanding correct in that mongodb acts like a "single database" but knows how to distribute data across disparate instances of mongodb (maybe located in different locations, etc)
2. Are each of those instances called shards? is that data replicated across all instances?

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MongoDB provides two types of scaling.

1. Read scaling: is provided by Replica Sets.
2. Write scaling is provided by Sharding.

Those links are a reasonable place to start.

There are also numerous slides and videos from the multiple Mongo conferences that have run recently. Here are some recent ones with use cases.

are each of those instances called shards? is that data replicated across all instances?

Think of a shard as a "slice" of your data. Each shard is generally composed of a replica set. So each shard has multiple computers managing replication of data.

is my understanding correct in that mongodb acts like a "single database" but knows how to distribute data across disparate instances of mongodb...

Sharding allows MongoDB to automatically distribute writes. But there's a little more to it, so I think it's best you work through some of the presentations.

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MongoDB has a great documentation. Issues like Sharding and Replica sets are documented in depth:

http://www.mongodb.org/display/DOCS/Sharding+Introduction http://www.mongodb.org/display/DOCS/Replica+Sets

Apart from that there are lot of presentations

http://www.10gen.com/presentations

and videos

http://www.10gen.com/presentations

dealing with your questions.

Please research first and come up with some more specific questions.