This book covers the use of Redis, an in-memory database/data structure server.

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Chapter 4: Keeping data safe and ensuring performance

This chapter covers

  • Persisting data to disk
  • Replicating data to other machines
  • Dealing with system failures
  • Redis transactions
  • Non-transactional pipelines
  • Diagnosing performance issues

In the last few chapters, you’ve learned about the variety of commands available in Redis and how they manipulate structures, and you’ve even solved a few problems using Redis. This chapter will prepare you for building real software with Redis by showing you how to keep your data safe, even in the face of system failure, and I’ll point out methods that you can use to improve Redis performance while preserving data integrity.

We’ll start by exploring the various Redis persistence options available to you for getting your data on disk. We’ll then talk about the use of replication to keep up-to-date copies of your data on additional machines for both performance and data reliability. Combining replication and persistence, we’ll talk about trade-offs you may need to make, and we’ll walk through a few examples of choosing persistence and replication options to suit your needs. We’ll then talk about Redis transactions and pipelines, and we’ll finish out the chapter by discussing how to diagnose some performance issues.

As we go through this chapter, our focus is understanding more about how Redis works so that we can first ensure that our data is correct, and then work toward making our operations on the data fast.

To start, let’s examine how Redis stores our information on disk so that, after restart, it’s still there.