hadoop 默认参数配置和调优设置

http://hadoop.apache.org/common/docs/current/hdfs-default.html

http://hadoop.apache.org/common/docs/current/core-default.html

http://hadoop.apache.org/common/docs/current/mapred-default.html

http://wiki.apache.org/hadoop/HowManyMapsAndReduces

新旧版本配置名对比：

http://hadoop.apache.org/common/docs/r0.23.0/hadoop-project-dist/hadoop-common/DeprecatedProperties.html

总入口

http://hadoop.apache.org/common/docs/current/

http://hadoop.apache.org/common/docs/current/hadoop-project-dist/hadoop-common/core-default.xml

http://hadoop.apache.org/common/docs/current/hadoop-project-dist/hadoop-hdfs/hdfs-default.xml

http://hadoop.apache.org/common/docs/current/hadoop-mapreduce-client/hadoop-mapreduce-client-core/mapred-default.xml