The essence of Reed-Solomon coding
Let’s say we want to store some data on multiple drives, so that we can recover from drive failures.
One obvious (and valid!) first attempt is to just store everything multiple times – usually called “mirroring”. The most common form of mirroring is to store things twice: if one drive fails, the data is still in the other.1
Reed-Solomon coding gives us much more flexibility, allowing us to store our data over n=k+t drives, so that any t drives can fail while still not losing data.2
Source: The essence of Reed-Solomon coding, an article by Francesco Mazzoli.