The dataset here is 17 TB+, so HDD storage is the only thing that's economically viable, especially for a service hosted as a hobby. :-) It doesn't really help that they DoS themselves, they still do it.

(After I limited connections to one per IP address, 90% of the problems went away. After I started blackholing users ignoring 503 responses, the remaining 10% were solved. I get the occasional “I didn't knooow, please give me access again” email now and then.)