Mikita Manko goes through a list of bottlenecks in MongoDB and suggest different ways to alleviate the pain (when possible):
I will try to describe here all potential performance bottlenecks and
possible solutions and tips for performance optimization, but first of all –
You should to ensure that MongoDB was the right choice for your project.
This blog is called myNoSQL and it is written by me, Alex Popescu, a software architect with a passion for open source and communities.
It records my readings, learnings, and opinions on NoSQL databases, polyglot persistence, and distributed systems -- subjects that I'm passionate about.
The opinions expressed here are my own, and no other party necessarily agrees with them.
If you feel I'm biased, I probably am.