Slave负责存储文件的具体内容，以块为单位，每块64MB
# Sanjay Ghemawat, Howard Gobioff, and Shun-Tak Leung. "The Google file system." ACM SIGOPS operating systems review. Vol. 37. No. 5. ACM, 2003.#Hadoop分布式文件系统 每台机器分配不同角色，称为Namenode和Datanode Namenode负责存储文件的元数据和在datanode中的具体位置 Datanode负责存储文件的具体内容，以块为单位Jeffrey Dean and Sanjay Ghemawat. "MapReduce: simplified data processing on large clusters." Communications of the ACM 51.1 (2008): 107-113.
== MapReduce==