I guess the network will be a bottleneck on Garage too. If you want high performance you might need a hybrid solution, like clustering of stateful apps on local storage as well as periodic full backups on a distributed storage.

Longhorn is pretty easy to use. Garage works well too. Ceph is harder to use but provides both block and object storage (s3).

Did you read the first paragraph of the article?

Probably the training data.

Hmm, but in this case you would be recording either the ads or the buffering.