Severl months ago, I saw the first article "LINE Starage" and didn't pay too much attention on it. Recently Someone discussed storage with me and let me remember it. So I found it again ( took me a bunch of time to look for ) and also took some pretty nice related articles here as well.
LINE Storage: Storing billions of rows in Sharded-Redis and HBase per Month
http://tech.naver.jp/blog/?p=1420
NoSQL Data Modeling Techniques
http://highlyscalable.wordpress.com/2012/03/01/nosql-data-modeling-techniques/
Cassandra vs MongoDB vs CouchDB vs Redis vs Riak vs HBase vs Membase vs Neo4j comparison
http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis
Hadoop + S3
http://wiki.apache.org/hadoop/AmazonS3
Apache Hadoop over OpenStack Swift
http://bigdatacraft.com/archives/349