In this chapter, you learned about maintenance and performance. You first learned about simple backup and restore using mongodump and mongorestore. You then went on to learn about creating indexes, including single field, multiple field, and multi-key. After that, you learned about replica sets, that is, primary and secondaries, how to deploy them, and adding or removing members. Finally, you learned about sharding, config servers, shard servers, range and hashed sharding strategies, and how to choose a shard key.
In the next chapter, you will learn various security-related considerations, in addition to learning how to secure a MongoDB database.