Hadoop之MapReduce

MapReduce基本概念及工作過程：

http://www.cnblogs.com/edisonchou/p/4287784.html

Shuffler過程

http://langyu.iteye.com/blog/992916

數據傾斜與shuffle類性能調優

http://blog.csdn.net/pengych_321/article/details/52260361