> Venti arenas stored on S3, with locally hosted indexes?

You can't just throw a whole arena into an S3 file, since the S3 API
doesn't support seeking within files.

On the other hand, an S3 bucket is essentially a big hash table, and
so is venti. So I opted for the simple approach of storing the blocks
themselves in S3. Given that, a local index doesn't help much. A local
bloom filter probably would help, but for now my server is stateless
(aside from cache).

Right now the server supports the basic venti api, but it falls over
if anything goes wrong on the connection. Once I make it more robust,
I'll put it in contrib for interested parties.