Here is a quick command to check if a hadoop cluster healthy or not.

run command

hdfs dfsadmin -report 

Output:

$ hdfs dfsadmin -report

Configured Capacity: 124468215873536 (113.20 TB)
Present Capacity: 124466727903232 (113.20 TB)
DFS Remaining: 124441188970496 (113.18 TB)
DFS Used: 25538932736 (23.78 GB)
DFS Used%: 0.02%
Under replicated blocks: 0
Blocks with corrupt replicas: 0
Missing blocks: 0
Missing blocks (with replication factor 1): 0

-------------------------------------------------
Live datanodes (2):

Name: 10.0.1.165:50010 (datanode2)
Hostname: datanode2.fibrevillage.com
Decommission Status : Normal
Configured Capacity: 36493640073216 (33.19 TB)
DFS Used: 10960756736 (10.21 GB)
Non DFS Used: 1843200 (1.76 MB)
DFS Remaining: 36482677473280 (33.18 TB)
DFS Used%: 0.03%
DFS Remaining%: 99.97%
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: Tue Nov 29 11:07:48 PST 2016


Name: 10.0.1.171:50010 (datanode1)
Hostname: datanode1.fibrevillage.com
Decommission Status : Normal
Configured Capacity: 87974575800320 (80.01 TB)
DFS Used: 14578176000 (13.58 GB)
Non DFS Used: 1486127104 (1.38 GB)
DFS Remaining: 87958511497216 (80.00 TB)
DFS Used%: 0.02%
DFS Remaining%: 99.98%
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: Tue Nov 29 11:07:47 PST 2016