On: Jepsen: Redis-Raft 1b3fbf6

[aphyr]

One of the things that surprised me about this analysis was just how many bugs we found that had to do with the actual Raft implementation. Usually when I test Raft-based systems the bugs are at the edges--like the coupling of the system to the Raft library, treating it like an externally-queryable log rather than the driver of a state machine, and so on. We found integration bugs here too, but also a fair number of issues in the Raft library itself--and this is despite Redis-Raft having existing integration tests!

This stuff is hard!

[evntdrvn → aphyr]

Has anyone approached Jepsen about running an analysis on the Erlang Ra implementation? I believe they've been running Jepsen tests internally, just curious if they're thinking about getting an official analysis at some point. Thanks for all that you folks do!! * https://github.com/rabbitmq/ra

[aphyr → evntdrvn]

No, we haven't talked yet, but I would like to someday. :)

[eproxus → aphyr]

Would love for Jepsen to take a stab at Erlang’s Mnesia database as well!

[kungfooguru → eproxus]

Not really worth it since distributed mnesia is basically CA (in terms of CAP) which shouldn't be a thing, but is in the case of mnesia :)

[Diggsey → aphyr]

Was the C Raft implementation in use a pre-existing library, or was it developed specifically for Redis-Raft?

[aphyr → Diggsey]

Pre-existing! It's a fork of willamt's https://github.com/willemt/raft/, which has been around since 2013, and has property-based fuzz testing! It really does look like it's got its own extensive tests; I'm surprised we found issues.

[anentropic → aphyr]

this is kind of terrifying