HDFS disk allocation

[#1]

does the location of these two parameters tell where HDFS will be using its space from?

NameNode directories=/u01/hadoop/hdfs/namenode 
DataNode directories=/u01/hadoop1/hdfs/data

also if i want to add more space to the cluster by adding another disk , how do i add it to the cluster?

[#2 · Accepted solution]

@Sami Ahmad Datanode directories is where HDFS data is actually stored while Namenode Directory is used for storing Namenode Metadata i.e. file, block information etc. associated with HDFS data stored on Datanodes. To add additional space to HDFS with additional disks, you should add disk to Datanode Directories i.e. if you add u02 to server(s), add the same to Datanode Directories.

DataNode directories=/u01/hadoop1/hdfs/data,/u02/hadoop1/hdfs/data

[#3]

thanks Pardeep.

so should we keep the HDFS disk seperate from the OS disk , i.e where the linux operating system is installed ?

[#4]

Yes that is recommended approach.