Is there a way or any command using which I can come to know the disk space of each datanode or the total cluster disk space?
I tried the command
dfs -du -h /
but it seems that I do not have permission to execute it for many directories and hence cannot get the actual disk space.
From UI:
http://namenode:50070/dfshealth.html#tab-datanode
---> which will give you all the details about datanode.
From command line:
To get disk space of each datanode:
sudo -u hdfs hdfs dfsadmin -report
---> which will give you the details of entire HDFS and the individual datanodes OR
sudo -u hdfs hdfs dfs -du -h /
---> which will give you the total disk usage of each folder under root / directory
You view the information about all datanodes and their disk usage in the namenode UI's Datanodes tab. Total cluster disk space can be seen in the summary part of the main page.
If you are using Hadoop cluster configured as simple security, you can execute the below command to get the usage of data nodes.
export HADOOP_USER_NAME=hdfs ;
* Above command can be used to get admin privilege in simple security, If you are using any other user for hdfs admin, replace hdfs with the respective hdfs admin user.
hadoop dfsadmin -report
Alternate option is to login to respective datanode and execute the below unix command to get disk utilization of that server.
df -h
Hadoop 3.2.0:
hduser@hadoop-node1:~$ hdfs dfs -df
Filesystem Size Used Available Use%
hdfs://hadoop-node1:54310 3000457228288 461352007680 821808787456 15%
hduser@hadoop-node1:~$
For human-readable numbers, use:
hduser@hadoop-node1:~$ hdfs dfs -df -h
Filesystem Size Used Available Use%
hdfs://hadoop-node1:54310 2.7 T 429.7 G 765.4 G 15%
hduser@hadoop-node1:~$
