Not sure about everyone, but probably yes. Imo the killer feature is durability and replication. You can use single disks if you don't care about data loss, but once you need to start replicating data you need a distributed filesystem.
Tectonic is Facebooks, Google's is Colossus. I'm not sure about the others.
Tectonic is Facebooks, Google's is Colossus. I'm not sure about the others.