文档介绍：HDFS Architecture Guide by Dhruba Borthakur Table of contents 1Introduction .......................................................................................................................3 2Assumptions and Goals .....................................................................................................3 Failure .......................................................................................................... 3 Data Access .................................................................................................3 Data Sets .............................................................................................................3 Coherency Model ............................................................................................. 4 “putation is Cheaper than Moving Data”................................................ 4 Across Heterogeneous Hardware and Software Platforms .........................4 3NameNode and DataNodes ............................................................................................... 4 4The File System Namespace ............................................................................................. 5 5Data Replication ................................................................................................................6 Placement: The First Baby Steps .................................................................... 7 Selection .......................................................................................................... 8 ...................................................................................................................... 8 6The Persistence of File System Metadata ......................................................................... 8 munication Protocols ......................................................................................... 9 8