About hadoop hdfs filesystem rename

Question

I am storing lots of data into hdfs. And I need to move the files from one folder to another.

May I ask generally how much is the cost of filesystem's rename method? Say I have to move terabytes of data.

Thank you very much.

Answer 1

Rename is a metadata-only operation in HDFS. Therefore it is be very cheap like it is in a normal POSIX filesystem, too. No data is moved. The only server involved is the namenode.

The source code for the rename can be found here. Pretty straight forward.