Detachable Block Storage: While our code repositories will live in the Docker images on our cloud computing instance, it's useful to have static storage if our apps store files or media. With the proliferation of S3-compatible storage providers and CDNs, it's not essential to have detachable storage on the provider level, but sometimes you just need a place to put some files. Think of Block Storage like an external drive attached to your instance: it's separate, but can only be attached to one instance at a time. It's possible to manage without detachable block storage; you could, for example, simulate it by having a second VM with a networked file system, but dedicated block storage is likely to be faster and definitely easier to deal with. In this guide, we'll use block storage both for our database file storage and for a network file share that will do double duty as a low-rent persistent storage layer for our containers.