At my consulting company, Inaka, we built this originally as a side project when we were using Redis and thought we needed multi-master larger-than-RAM datasets, but then we ended up moving to CouchDB for that project.
It's currently a research project for us and we have an intern from Uppsala University working on the HA features including paxos leader election and multi-master conflict resolution. See the mutinode branch. Some people have added some additional database backends, but I don't know of any serious production users yet.
I gave a talk on it at the 2012 Erlang Factory as it's entirely Erlang-based. Here's the talk - http://vimeo.com/42630498
Benefits over Redis: Faster startup time over big datasets, pluggable backends, (eventually) Multi-master and HA (with a different approach than Redis is currently taking with Sentinel).
Drawbacks: 3x to 10x slower on all operations. We've done no work to optimize.
It's really a much longer story. We use Redis and Couch together. Redis for caching, Couch for long-term storage.
Whether Couch has or doesn't have Map/Reduce is irrelevant, really. Couch Map/Reduce is a toy (just like Riak) and is not to be trusted. We avoid it as much as possible.
I guess I don't see the point of a Redis clone in Erlang when it would be easier to tack use cases onto something that already exists, namely Riak. It's a key-value store, it's in Erlang, it's distributed, it's getting a full-text search and it has adjustable parameters so you can pick how you want to deal with the tyranny of the CAP theorem.
The only think Riak doesn't have is a high-speed RAM-based data structure capability. But hey, Redis does that. ;-)
It's currently a research project for us and we have an intern from Uppsala University working on the HA features including paxos leader election and multi-master conflict resolution. See the mutinode branch. Some people have added some additional database backends, but I don't know of any serious production users yet.
I gave a talk on it at the 2012 Erlang Factory as it's entirely Erlang-based. Here's the talk - http://vimeo.com/42630498
Benefits over Redis: Faster startup time over big datasets, pluggable backends, (eventually) Multi-master and HA (with a different approach than Redis is currently taking with Sentinel).
Drawbacks: 3x to 10x slower on all operations. We've done no work to optimize.