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What is the difference between volumes and folders?

Contributor

Hi experts,

Can someone please explain the difference between volumes and folders in hadoop?

 

Thanks,

1 ACCEPTED SOLUTION

Rising Star

Hi @ryu 

Volume:

As described in HDFS architecture, the NameNode stores metadata while the DataNodes store the actual data content. Each DataNode is a computer which usually consists of multiple disks (in HDFS’ terminology, volumes). A file in HDFS contains one or more blocks. A block has one or multiple copies (called Replicas), based on the configured replication factor. A replica is stored on a volume of a DataNode, and different replicas of the same block are stored on different DataNodes. 
 
Directory(usually don't say it folders):
like other file system, hdfs directory is hierarchical file structure
 
Regards,
Will

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2 REPLIES 2

Rising Star

Hi @ryu 

Volume:

As described in HDFS architecture, the NameNode stores metadata while the DataNodes store the actual data content. Each DataNode is a computer which usually consists of multiple disks (in HDFS’ terminology, volumes). A file in HDFS contains one or more blocks. A block has one or multiple copies (called Replicas), based on the configured replication factor. A replica is stored on a volume of a DataNode, and different replicas of the same block are stored on different DataNodes. 
 
Directory(usually don't say it folders):
like other file system, hdfs directory is hierarchical file structure
 
Regards,
Will

Contributor

Hi @willx ,
Is there a way to see if the hadoop path is a volume or a directory?

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