[bug#52555] [RFC PATCH v2 0/5] Decentralized substitute distribution with ERIS

[pukkamustard <pukkamustard@posteo.net>]

Maxime Devos <maximedevos@telenet.be> writes:

>> I think it is important that we do not rely on IPFS for block
>> storage. The decentralized block distribution should work even if the
>> IPFS daemon is not available.
>
> Do we need a database at all?
>
> E.g., if the client cannot download the data in the range [start, end]
> because the corresponding block has disappeared, can it not simply
> download that range from https://ci.guix.gnu.org/nar/[...]
> (not sure about the URI) using a HTTP range request?

This does not work as the mapping from block reference to location in
NAR can not be known by the client who only holds the ERIS
URN. Furthermore, some blocks will be intermediary nodes - they hold
references to content blocks (or other intermediary nodes) but not
content itself.

> (Afterwards, the client should insert the block(s) back into
> IPFS/GNUnet/whatever, maybe using this proposed ‘in-file block store’
> such that other clients (using the same DHT mechanism) can benefit.)

It might make sense for some clients to make content available to other
clients and to go trough the extra effort of putting blocks back into
IPFS/GNUNet/whatever. But this should be optional. Maybe we can call
such clients "caching peers"?

IMO A client should by default only deal with things that are strictly
necessary for getting substitutes. The substistute servers (and caching
peers) should make sure substitutes are available to clients, whether
over IPFS/GNUNet/whatever or plain old HTTP.

-pukkamustard