八、hdfs文件系统副本块数量的配置

1、配置方式

2、实际操作演示

（1）在Hadoop用户的根目录下创建text.txt文件

（2）上传文件

hadoop@node1:~$ hdfs dfs -ls hdfs://node1:8020/
Found 4 items
drwxr-xr-x   - hadoop supergroup          0 2023-11-21 23:06 hdfs://node1:8020/home
-rw-r--r--   2 hadoop supergroup         35 2023-11-26 22:54 hdfs://node1:8020/text.txt
-rw-r--r--   3 hadoop supergroup         27 2023-11-26 22:57 hdfs://node1:8020/three_text.txt
drwx------   - hadoop supergroup          0 2023-11-18 12:21 hdfs://node1:8020/user

（3）修改副本数

hadoop@node1:~$ hdfs dfs -setrep 1 hdfs://node1:8020/three_text.txt
Replication 1 set: hdfs://node1:8020/three_text.txt
hadoop@node1:~$ hdfs dfs -ls hdfs://node1:8020/
Found 4 items
drwxr-xr-x   - hadoop supergroup          0 2023-11-21 23:06 hdfs://node1:8020/home
-rw-r--r--   2 hadoop supergroup         35 2023-11-26 22:54 hdfs://node1:8020/text.txt
-rw-r--r--   1 hadoop supergroup         27 2023-11-26 22:57 hdfs://node1:8020/three_text.txt
drwx------   - hadoop supergroup          0 2023-11-18 12:21 hdfs://node1:8020/user

3、fsck命令检查文件的副本数

（1）结果演示：

hadoop@node1:~$ hdfs fsck hdfs://node1:8020/text.txt -files -blocks -locations
Connecting to namenode via http://node1:9870/fsck?ugi=hadoop&files=1&blocks=1&locations=1&path=%2Ftext.txt
FSCK started by hadoop (auth:SIMPLE) from /192.168.88.101 for path /text.txt at Sun Nov 26 23:07:44 CST 2023

/text.txt 35 bytes, replicated: replication=2, 1 block(s):  OK
0. BP-1383297113-192.168.88.101-1699274849934:blk_1073741835_1012 len=35 Live_repl=2  [DatanodeInfoWithStorage[192.168.88.103:9866,DS-89bf9985-fca9-4717-bdd1-1476f0b98a0f,DISK], DatanodeInfoWithStorage[192.168.88.101:9866,DS-bc41ebe7-7da0-4097-813b-7a025fba1b99,DISK]]


Status: HEALTHY
 Number of data-nodes:  3
 Number of racks:               1
 Total dirs:                    0
 Total symlinks:                0

Replicated Blocks:
 Total size:    35 B
 Total files:   1
 Total blocks (validated):      1 (avg. block size 35 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:     2.0
 Missing blocks:                0
 Corrupt blocks:                0
 Missing replicas:              0 (0.0 %)
 Blocks queued for replication: 0

Erasure Coded Block Groups:
 Total size:    0 B
 Total files:   0
 Total block groups (validated):        0
 Minimally erasure-coded block groups:  0
 Over-erasure-coded block groups:       0
 Under-erasure-coded block groups:      0
 Unsatisfactory placement block groups: 0
 Average block group size:      0.0
 Missing block groups:          0
 Corrupt block groups:          0
 Missing internal blocks:       0
 Blocks queued for replication: 0
FSCK ended at Sun Nov 26 23:07:44 CST 2023 in 1 milliseconds


The filesystem under path '/text.txt' is HEALTHY

（2）分析