I have been watching Hadoop and Hbase for a while because I have often run into issues with SQL and web apps. I have long conversations with my colleagues (Kevin, Steve, Conrad and Joe) about a fundemenatl change that needs to happen at the data layer in web application design. The days of good old SQL are nearing the end. A shift is going to happen and perhaps it will be Hadoop and Hbase.
Here are some project links to check out if you find data layer interesting
Hadoop – http://hadoop.apache.org/
HBase – http://hadoop.apache.org/hbase/
Hadoop Wiki - http://wiki.apache.org/hadoop/
HBase Wiki - http://wiki.apache.org/hadoop/Hbase
GFS paper - http://labs.google.com/papers/gfs.html
MapReduce paper - http://labs.google.com/papers/mapreduce.html
BigTable Paper - http://labs.google.com/papers/bigtable.html
Some other interesting projects to check out:
Cascading – http://www.cascading.org/
Pig – http://hadoop.apache.org/pig/
Hive – http://hadoop.apache.org/hive/
Pigi – http://www.pigi-project.org/
ZooKeeper – http://hadoop.apache.org/zookeeper/