A really cool technique that’s commonly used in object storage such as S3 to improve durability is called erasure coding. Let’s take a look at how it works. Erasure coding deals with data durability differently from replication. It chunks data into smaller pieces (placed on different servers) and creates parities for redundancy. In the event of failures, we can use chunk data and parities to reconstruct the data. Let’s take a look at a concrete example (4 + 2 erasure coding) as shown in Figure 1.