It's always worth pointing out with Minio: they optimized for disk usage (with erasure encoding) and came up with an object store that tops out at 16 drives.

"Note that with distributed Minio you can play around with the number of nodes and drives as long as the limits are adhered to. For example, you can have 2 nodes with 4 drives each, 4 nodes with 4 drives each, 8 nodes with 2 drives each, and so on." https://docs.minio.io/docs/distributed-minio-quickstart-guid...

Minio is the least scale-able of the open source object stores. Check out Swift, Ceph, Manta, or Riak CS.