Documentation detailing difference to/migration from Bitcoin Core missing

[arnuschky]

Unless I am mistaken, there's no document that clearly details the difference to Bitcoin Core, or describes a migration path. This would be really useful for people that consider moving away from Bitcoin Core.

Some questions this document might cover:

• incompatibilities
• differing default features and how to enable them
• are there migration tools for Bitcoin Core's databases and wallets

I propose to collect related questions here to make writing this document easier.

[arnuschky]

Question (the one that actually drove me to look for said document): We're currently using Bitcoin Core with -txindex=1. However, I don't have to explicitly enable the index in btcd, right? I couldn't find any location where this is said explicitly.

[davecgh]

I don't believe there is a document, but that is a good idea. Given the various uses, providing a specific migration guide might prove challenging since that would largely depend on how it's being used, but documenting any major differences seems like a reasonable thing to do. It could be added to the documentation.

For now, I'll answer your questions here and perhaps it can become the start of such a document.

The biggest difference is the fact that btcd only provides chain services. All wallet functionality has intentionally been split into the separate btcwallet daemon. Bitcoin Core, on the other hand, currently combines everything into the daemon including both chain and wallet functionality (though I believe they have been working towards splitting the wallet functionality out as well). Bitcoin-qt also combines in wallet GUI functionality.

As far as chain services:

• Incompatibilies:
  • The are no known incompatibilities in any of the core protocol or RPC calls.
  • However, btcd currently does not support JSON-RPC 2.0 batching mode which some things such as electrum use. btcd will be adding support for this in the near future.
• Differing default features:
  • Bitcoin Core requires the -txindex=1 option to enable the transaction index. Btcd provides the transaction index by default and has no option to disable it.
  • Bitcoin Core does not have TLS protection enabled for RPC connections by default nor does it require it for remote connections. Btcd has TLS enabled by default and requires it for remote connections (non-localhost). TLS can be disable with btcd by using the --notls option, but only when listening solely on localhost interfaces.
  • Bitcoin Core requires the RPC server to be configured in order to start the daemon. Btcd runs without it and will only enable the RPC server once it has been configured.
• Are there migration tools for bitcoind's databases and wallets?
  • There are currently no migration tools for converting the Bitcoin Core database directly to btcd. However, a tool is provided to import bootstrap.dat (https://github.com/btcsuite/btcd/blob/master/docs/using_bootstrap_dat.md). It would be possible to use the Bitcoin Core linearize.py script to create a new bootstrap.dat file and then use the btcd addblock utility to import it. That said, it's probably not worth the effort as it would most likely be faster to simply redownload the chain.
  • As mentioned above, btcd itself intentionally split the wallet functionality out of the core chain service daemon, so it does not have any wallet functionality, thus the wallet question does not apply directly. However, btcwallet does support the WIF format that is dumped from the Bitcoin Core wallet via the dumpprivkey RPC call. It can be imported with the same importprivkey RPC call that Bitcoin Core uses.
  • The differences in the Bitcoin Core wallet functionality and btcwallet really will probably end up needing its own document as btcwallet is different than Bitcoin Core's wallet in many ways, and it currently has open pull requests that will be bring a ton of new functionality to it such as BIP0032 hierarchical deterministic keys and proper accounts support which will be further differences.

Also, I'd like to point out that btcwallet is a daemon just like btcd. In other words, it's intended for programmatic access. That means it does not have a shiny GUI like Bitcoin-qt/Armory/etc that most end users are used to interfacing with. There is the btcgui project which is a proof of concept on how such a GUI can be built on top of btcwallet, however, since btcgui is only a proof of concept, it is no where near ready for end users.

[arnuschky]

Wow, amazingly comprehensive answer (in such a short time). Thank you, that answers my question relating -txindex. Good to know for RPC with TLS, I can see this being a major trap when moving an existing (and insecure ;)) installation from Bitcoin Core to btcd.

[davecgh]

This was not supposed to be closed.

[manan19]

For a temporary solution,

set port=8339 in bitcoin.conf and start bitcoind
btcd --testnet --addpeer=127.0.0.1:8339 --maxpeers=1