you need to know all of the hosts that have that file (not always public knowledge)
You merely need to download the file over and over... which causes the renter to run out of money. Same as a DOS attack downloading a web page.
forcing attackers to spend significant monetary resources executing an attack.
Attackers always spend the same money that legitimate hosts spend. The "attacker" here is running completely legitimate, full copies of the protocol. The only difference is that they are running multiple docker containers on the same machine... rather than running on multiple machines. There is simply no way to know that outside of IP. Just like a DOS attacker runs a fully legitimate client, so too a Sybil attacker runs a legitimate server.
The really nice thing about both DDOS and Sybil attack prevention is that it's not a consensus layer problem.
I think that succinctly sums up what I
meant in the original post.
Since DDOS and Sybil are inverted forms of similar attacks (multiple clients vs multiple hosts), these decentralized storage networks haven't introduced a "new" problem to the domain of hosting. Indeed, any existing cloud hosting provider could, today, "claim redundancy" on your data... but physically locate it on the same machine. The solution to this problem lies in the transport and social layers... not the consensus protocol.