Hadoop命令-fsck

在HDFS中，提供了fsck命令，用于检查HDFS上文件和目录的健康状态、获取文件的block块信息和位置信息等。

具体命令介绍：

-move: 移动损坏的文件到/lost+found目录下
-delete: 删除损坏的文件
-openforwrite: 输出检测中的正在被写的文件
-list-corruptfileblocks: 输出损坏的块及其所属的文件
-files: 输出正在被检测的文件
-blocks: 输出block的详细报告（需要和-files参数一起使用）
-locations: 输出block的位置信息（需要和-files参数一起使用）
-racks: 输出文件块位置所在的机架信息（需要和-files参数一起使用）

例如要查看HDFS中某个文件的block块的具体分布，可以这样写：
hadoop fsck /your_file_path -files -blocks -locations -racks
示例：

#hdfs fsck /tmp/test/input/word.log  -files -blocks  -locations -racks 
Connecting to namenode via http://c12-138:50070
FSCK started by root (auth:SIMPLE) from /10.254.13.141 for path /tmp/test/input/word.log at Wed Aug 10 17:17:45 CST 2016
/tmp/test/input/word.log 70 bytes, 1 block(s):  OK
0. BP-1390896613-10.254.12.138-1467366342106:blk_1074295976_555178 len=70 Live_repl=3 [/default/10.254.13.141:50010, /default/10.254.12.139:50010, /default/10.254.12.138:50010]

Status: HEALTHY
 Total size:    70 B
 Total dirs:    0
 Total files:   1
 Total symlinks:                0
 Total blocks (validated):      1 (avg. block size 70 B)
 Minimally replicated blocks:   1 (100.0 %)
 Over-replicated blocks:        0 (0.0 %)
 Under-replicated blocks:       0 (0.0 %)
 Mis-replicated blocks:         0 (0.0 %)
 Default replication factor:    3
 Average block replication:     3.0
 Corrupt blocks:                0
 Missing replicas:              0 (0.0 %)
 Number of data-nodes:          10
 Number of racks:               1
FSCK ended at Wed Aug 10 17:17:45 CST 2016 in 1 milliseconds


The filesystem under path '/tmp/test/input/word.log' is HEALTHY