为了今后对集群读写文件所需时间有所估算，可以对集群读写性能进行测试
1） 测试HDFS写性能
测试内容：向HDFS集群写10个128M的文件
[atguigu@hadoop102 mapreduce]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.7.2-tests.jar TestDFSIO -write -nrFiles 10 -fileSize 128MB
2）测试HDFS读性能
测试内容：读取HDFS集群10个128M的文件
[atguigu@hadoop102 mapreduce]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.7.2-tests.jar TestDFSIO -read -nrFiles 10 -fileSize 128MB
3）删除测试生成数据
[atguigu@hadoop102 mapreduce]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.7.2-tests.jar TestDFSIO -clean
4）使用Sort程序评测MapReduce
（1）使用RandomWriter来产生随机数，每个节点运行10个Map任务，每个Map产生大约1G大小的二进制随机数
[atguigu@hadoop102 mapreduce]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.2.jar randomwriter random-data
（2）执行Sort程序
[atguigu@hadoop102 mapreduce]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.2.jar sort random-data sorted-data
（3）验证数据是否真正排好序了
[atguigu@hadoop102 mapreduce]$ hadoop jar /opt/module/hadoop-2.7.2/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.2.jar testmapredsort -sortInput random-data -sortOutput sorted-data