1、hadoop fs -setrep
代码语言：javascript复制setrep
Usage: hadoop fs -setrep [-R] [-w] <numReplicas> <path>
Changes the replication factor of a file. If path is a directory then the command recursively
changes the replication factor of all files under the directory tree rooted at path.
Options:
The -w flag requests that the command wait for the replication to complete. This can potentially take a very long time.
The -R flag is accepted for backwards compatibility. It has no effect.
Example:
hadoop fs -setrep -w 3 /user/hadoop/dir1
Exit Code:
Returns 0 on success and -1 on error.2、示例演示
（1）查看文件副本数，第二列的3表示3副本
代码语言：javascript复制[root@node1 ~]# hadoop fs -ls /test
18/01/23 01:24:46 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Found 4 items
-rw-r--r-- 3 root hbase 100797385 2018-01-22 22:26 /test/a.tar
-rw-r--r-- 3 root hbase 100854145 2018-01-22 22:26 /test/a.zip
-rw-r--r-- 3 root hbase 38009648 2018-01-22 22:27 /test/kafka-2.10-0.10.2.0.x86_64.rpm
-rw-r--r-- 3 root hbase 2374608 2018-01-22 22:27 /test/zookeeper-3.4.6-1.x86_64.rpm
[root@node1 ~]# （2）修改/test目录的副本数
代码语言：javascript复制[root@node1 ~]# hadoop fs -setrep -w 2 /test
18/01/23 01:24:58 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Replication 2 set: /test/a.tar
Replication 2 set: /test/a.zip
Replication 2 set: /test/kafka-2.10-0.10.2.0.x86_64.rpm
Replication 2 set: /test/zookeeper-3.4.6-1.x86_64.rpm
Waiting for /test/a.tar ...
WARNING: the waiting time may be long for DECREASING the number of replications.
. done
Waiting for /test/a.zip ... done
Waiting for /test/kafka-2.10-0.10.2.0.x86_64.rpm ... done
Waiting for /test/zookeeper-3.4.6-1.x86_64.rpm ... done
[root@node1 ~]# （3）再次查看副本数，第二列变成了2
代码语言：javascript复制[root@node1 ~]# hadoop fs -ls /test
18/01/23 01:25:12 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Found 4 items
-rw-r--r-- 2 root hbase 100797385 2018-01-22 22:26 /test/a.tar
-rw-r--r-- 2 root hbase 100854145 2018-01-22 22:26 /test/a.zip
-rw-r--r-- 2 root hbase 38009648 2018-01-22 22:27 /test/kafka-2.10-0.10.2.0.x86_64.rpm
-rw-r--r-- 2 root hbase 2374608 2018-01-22 22:27 /test/zookeeper-3.4.6-1.x86_64.rpm
[root@node1 ~]# 
