File Systems

There are several common ways to store binary information:

Database or key-value store (e.g. PostgreSQL, SQLite) - Good for small files or a finite amount of files which fit within the confines of a database.
Object store (e.g. S3) - same as a key-value store but typically designed to scale lots of files across multiple HDDs and hosts.
File systems (e.g. EXT4) - good for files where certain operations benefit from a hierarchical data structure, e.g. list, delete. File systems typically come with metadata such as permissions and owners.
Block storage - you get raw disk access but need to layout your binary data manually and in fixed block sizes.

Standard File Systems

MergerFS - a union file system to combine multiple folders on a single computer.

The create a view of one or more block storage, typically using one or more block storage.

Minio - S3-compatible object store
Ceph - joins drives across multiple computers. Has block, file, and object storage APIs.
Rook - deployment of Ceph using Kubernetes
SeaweedFS - joins drives across multiple computers to object storage APIs (incl. S3). Has file storage when paired with a database using the SeaweedFS Filer.

GlusterFS - joins filesystem directories across multiple computers
Ceph - joins drives across multiple computers. Has block, file, and object storage APIs.
JuiceFS - creates a POSIX-compatable file storage using an S3 object storage and metadata database.