In this chapter, we explored sharding, one of the most interesting features of MongoDB. We started with an architectural overview of sharding and moved on to how we can design a shard and choose the right shard key.

We learned about monitoring, administration, and the limitations that come with sharding. We also learned about mongos, the MongoDB sharding router that directs our queries to the correct shard. Finally, we discussed recovery from common failure types in a MongoDB sharded environment.

The next chapter on fault tolerance and high availability will offer some useful tips and tricks that have not been covered in the 11 other chapters.