In the previous two recipes, we learned about the RDB option for Redis data persistence. However, using RDB for data persistence does not provide very strong durability. As mentioned, an RDB data dump only contains a point-in-time data snapshot of Redis. Although Redis dumps data into the RDB file periodically, the data between two RDB dumps will be lost permanently when a Redis process crashes, or there is a hardware failure. AOF is an append-only log file that records the write commands of the Redis Server. The data durability of AOF is higher than RDB, because every write command is appended to the file. In this recipe, we will show you how to enable AOF in Redis and introduce some important configuration parameters of AOF.
You need to finish the installation of the Redis Server, as we described in the Downloading and installing Redis recipe in Chapter 1,Getting Started with Redis.