On Fri, Jul 24, 2009 at 4:20 PM, ashish pareek <[email protected]> wrote:
> Hi Everybody, > > From last few weeks I am trying to find out what data > structure does Hadoop uses to store files and directories Meta-data > information. If any one can point out the exact source file where this > source code is, it will help me a lot. > > Thank you in advance. > > You probably want to take a look at org.apache.hadoop.hdfs.server.namenode package (specifically NameNode.java, FSNamesystem.java might be interesting). Essentially it maintains a bunch of tables (maps from filename -> blocklist, block -> datanodes, etc). Some of them are serialized to disk (ie FSImage) while others are just in-memory and are re-constructed after every restart. -- Harish Mallipeddi http://blog.poundbang.in
