[Bitcoin-development] Service bits for pruned nodes

[Ricardo Filipe]

We would only end up with few copies of the historic data if users
could choose what parts of the blockchain to store. Simply store
chunks randomly, according to users available space, and give priority
to the "N most recent" chunks to have more replicas in the network.

You don't need bittorrent specifically for a DHT, if publicity is a
problem. There are many DHT proposals and implementations, and i bet
one of them should be more suitable to the bitcoin network than
bittorrent's.

>On Sun, Apr 28, 2013 at 9:29 AM, Mike Hearn <mike at ...> wrote:
>> I'd imagined that nodes would be able to pick their own ranges to keep
>> rather than have fixed chosen intervals. "Everything or two weeks" is rather
>
>X most recent is special for two reasons:  It meshes well with actual demand,
>and the data is required for reorganization.
>
>So whatever we do for historic data, N most recent should be treated specially.
>
>But I also agree that its important that <everything> be splittable into ranges
>because otherwise when having to choose between serving historic data
>and— say— 40 GB storage, a great many are going to choose not to serve
>historic data... and so nodes may be willing to contribute 4-39 GB storage
>to the network there will be no good way for them to do so and we may end
>up with too few copies of the historic data available.
>
>As can be seen in the graph, once you get past the most recent 4000
>blocks the probability is fairly uniform... so "N most recent" is not a
>good way to divide load for the older blocks. But simple ranges— perhaps
>quantized to groups of 100 or 1000 blocks or something— would work fine.
>
>This doesn't have to come in the first cut, however— and it needs new
>addr messages in any case.