Riak 0.12 Released
downloads.basho.com
downloads.basho.com
"Riak is a Dynamo-inspired key/value store that scales predictably and easily. Riak also simplifies development by giving developers the ability to quickly prototype, test, and deploy their applications
A truly fault-tolerant system, Riak has no single point of failure. No machines are special or central in Riak, so developers and operations professionals can decide exactly how fault-tolerant they want and need their applications to be."
http://blog.heroku.com/archives/2010/7/20/nosql/
Riak's nice for redundancy and high availability stuff, and scales dynamically by adding instances.
http://blog.mozilla.com/data/2010/05/18/riak-and-cassandra-a...
Anybody used it before?
riak is just about 1 years old from an open source perspective but is in use in a few production environments and had been in development a few yrs before going open source, afaik. What I like most about riak is the 'no special node' feature and the very close adherence to amazon's dynamo lineage. easy scale up - and easy scale down. adherence to dynamo also means you can fine tune your r/w/n values at a granular level. beyond that, the fact that you can do virtually everything there is to do in riak over http is fantastic. other access pathways are erlang client and protobuffs. another major feature of riak is that you can link keys together with link headers. admin wise, riak is very simple to get up and running either in a dev environment or production.
the drawbacks against riak are that there is no ordering of keys, no select * keys, no select range. listing all keys is expensive. you almost have to keep your own internal index of keys if you want to maintain performance over m/r jobs in any sort of realtime fashion.
im glossing over lots of finer points but if you have specific questions the irc is well manned and so is the mailing list.
A big plus for Riak is the fact that you can actually shard riak automatically. Couch has to be sharded manually which destroys map/reduce.