hbase-architecture
https://www.mapr.com/blog/in-depth-look-hbase-architecture
http://stackoverflow.com/questions/40067933/hbase-whats-the-difference-between-wal-and-memstore
https://www.mapr.com/blog/in-depth-look-hbase-architecture
http://zh.hortonworks.com/blog/apache-hbase-region-splitting-and-merging/
http://hbase.apache.org/book.html#client
http://www-users.cs.umn.edu/~prashant/reports/hbaseReport.pdf
http://www.slideshare.net/caroljmcdonald/h-base-nosqlcarol
http://hadoop-hbase.blogspot.com.by/2012/05/hbase-hdfs-and-durable-sync.html
http://blog.cloudera.com/blog/2012/06/hbase-io-hfile-input-output/
http://blog.cloudera.com/blog/2012/06/hbase-write-path/
http://www.larsgeorge.com/2009/10/hbase-architecture-101-storage.html
http://stackoverflow.com/questions/32755662/hbase-wal-file-and-hdfs-data-staging?rq=1
https://www.quora.com/Why-does-HBase-keep-WAL-on-HDFS-instead-of-local-disks
https://hbase.apache.org/0.94/apidocs/org/apache/hadoop/hbase/client/HConnection.html
http://stackoverflow.com/questions/18719042/hbase-how-put-get-knows-which-region-server-to-write-to