DFS Used%: NaN%问题

一.问题描述：

[root@master sbin]# hdfs dfsadmin -report

Configured Capacity: 0 (0 B)

Present Capacity: 0 (0 B)

DFS Remaining: 0 (0 B)

DFS Used: 0 (0 B)

DFS Used%: NaN%

Under replicated blocks: 0

Blocks with corrupt replicas: 0

Missing blocks: 0

Missing blocks (with replication factor 1): 0

Pending deletion blocks: 0

二.问题导致可能原因：

1）多次格式化导致的，可以尝试删除hdfs下的data目录、name目录、tmp目录后格式，然后重新启动；

2）没有关闭防火墙，可以通过以下命令检查是否关闭了防火墙，如果没有关闭先关闭对应节点的防火墙

[root@slave1 data]# service iptables status

iptables: Firewall is not running.

3）不在同一个网络，需要相互ping通

4）检查namenode节点上的cat /etc/hosts下有没有注释127.0.0.1映射表，如果没有先注释再重新启动

[root@master hadoop-3.0.0-alpha4]# cat /etc/hosts

127.0.0.1   master localhost

::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

192.168.28.130 www

192.168.28.130 master

192.168.28.136 slave1

192.168.28.137 slave2

发现有127.0.0.1映射，先注释掉再启动hadoop相关服务

[root@master sbin]# ./start-all.sh

Starting namenodes on [master]

Starting datanodes

Starting secondary namenodes [master]

Starting resourcemanager

Starting nodemanagers

三.问题解决后，运行结果如下：

[root@master sbin]# hdfs dfsadmin -report

Configured Capacity: 202921664512 (188.99 GB)

Present Capacity: 166830989312 (155.37 GB)

DFS Remaining: 166830940160 (155.37 GB)

DFS Used: 49152 (48 KB)

DFS Used%: 0.00%

Under replicated blocks: 0

Blocks with corrupt replicas: 0

Missing blocks: 0

Missing blocks (with replication factor 1): 0

Pending deletion blocks: 0

-------------------------------------------------

Live datanodes (2):

Name: 192.168.28.136:9866 (slave1)

Hostname: slave1

Decommission Status : Normal

Configured Capacity: 101460832256 (94.49 GB)

DFS Used: 24576 (24 KB)

Non DFS Used: 12891869184 (12.01 GB)

DFS Remaining: 83415031808 (77.69 GB)

DFS Used%: 0.00%

DFS Remaining%: 82.21%

Configured Cache Capacity: 0 (0 B)

Cache Used: 0 (0 B)

Cache Remaining: 0 (0 B)

Cache Used%: 100.00%

Cache Remaining%: 0.00%

Xceivers: 1

Last contact: Thu Jun 07 10:52:01 CST 2018

Last Block Report: Thu Jun 07 10:51:14 CST 2018

Name: 192.168.28.137:9866 (slave2)

Hostname: slave2

Decommission Status : Normal

Configured Capacity: 101460832256 (94.49 GB)

DFS Used: 24576 (24 KB)

Non DFS Used: 12890992640 (12.01 GB)

DFS Remaining: 83415908352 (77.69 GB)

DFS Used%: 0.00%

DFS Remaining%: 82.21%

Configured Cache Capacity: 0 (0 B)

Cache Used: 0 (0 B)

Cache Remaining: 0 (0 B)

Cache Used%: 100.00%

Cache Remaining%: 0.00%

Xceivers: 1

Last contact: Thu Jun 07 10:52:01 CST 2018

Last Block Report: Thu Jun 07 10:51:14 CST 2018