hdfs损坏block定位以及修复

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信息和位置信息等。
fsck命令必须由HDFS超级用户来执行，普通用户无权限。
可通过hdfs fsck来查看该命令的帮助文档，如下图所示：

1.手工修复 hdfs debug

1）造一份数据上传到hdfs

 [hadoop@hadoop001 data]$ hadoop fs -put test.txt /blockrecover

2）通过hdfs fsck定位该文件块所在位置

[hadoop@hadoop001 data]$ hdfs fsck /blockrecover/test.txt -files -blocks -locations

19/04/04 12:38:47 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Connecting to namenode via http://hadoop001:50070
FSCK started by hadoop (auth:SIMPLE) from /192.168.0.108 for path /blockrecover/test.txt at Thu Apr 04 12:38:48 PDT 2019
/blockrecover/test.txt 2 bytes, 1 block(s):  Under replicated BP-1279338148-192.168.199.200-1491145566665:blk_1073742362_1538. Target Replicas is 3 but found 1 replica(s).
0. BP-1279338148-192.168.199.200-1491145566665:blk_1073742362_1538 len=2 Live_repl=1 [DatanodeInfoWithStorage[192.168.0.108:50010,DS-9841e6c3-9a74-4bc8-869e-3543dcf7de90,DISK]]

Status: HEALTHY
 Total size:	2 B
 Total dirs:	0
 Total files:	1
 Total symlinks:		0
 Total blocks (validated):	1 (avg. block size 2 B)
 Minimally replicated blocks:	1 (100.0 %)
 Over-replicated blocks:	0 (0.0 %)
 Under-replicated blocks:	1 (100.0 %)
 Mis-replicated blocks:		0 (0.0 %)
 Default replication factor:	3
 Average block replication:	1.0
 Corrupt b