In this chapter, we discussed some common data modeling patterns to avoid. However, it would be impossible to cover every bad choice a user might make, so it's important to focus on understanding the fundamentals of sound design. This will give you a foundation that will allow you to make correct data modeling decisions on whatever problem you may encounter.

As we have also seen in this chapter, sometimes Cassandra isn't the right tool for the problem at hand. Hopefully, you can now recognize when this is the case, and choose the right tool for the right job.

It is now time to wrap up this book by taking a look at ways in which things can go wrong when running Cassandra. While it is a highly fault-tolerant system, you will rest easy if you know what to do when the unexpected happens.