org.apache.hadoop.dfs
Class DFSck

java.lang.Object
  org.apache.hadoop.util.ToolBase
      org.apache.hadoop.dfs.DFSck

All Implemented Interfaces:

Configurable, Tool

public class DFSck
extends ToolBase

This class provides rudimentary checking of DFS volumes for errors and sub-optimal conditions.

The tool scans all files and directories, starting from an indicated root path. The following abnormal conditions are detected and handled:

• files with blocks that are completely missing from all datanodes.
  In this case the tool can perform one of the following actions:
  • none (NamenodeFsck.FIXING_NONE)
  • move corrupted files to /lost+found directory on DFS (NamenodeFsck.FIXING_MOVE). Remaining data blocks are saved as a block chains, representing longest consecutive series of valid blocks.
  • delete corrupted files (NamenodeFsck.FIXING_DELETE)
• detect files with under-replicated or over-replicated blocks

Additionally, the tool collects a detailed overall DFS statistics, and optionally can print detailed statistics on block locations and replication factors of each file.

Author:

Andrzej Bialecki

Field Summary

Fields inherited from class org.apache.hadoop.util.ToolBase

conf

Constructor Summary

DFSck(Configuration conf)
Filesystem checker.

Method Summary

static void	main(String[] args)
int	run(String[] args) execute the command with the given arguments

Methods inherited from class org.apache.hadoop.util.ToolBase

doMain, getConf, setConf

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DFSck

public DFSck(Configuration conf)
      throws Exception

Filesystem checker.

Parameters:

conf - current Configuration

Throws:

Exception

Method Detail

run

public int run(String[] args)
        throws Exception

Description copied from interface: Tool

execute the command with the given arguments

Parameters:

args -

Returns:

exit code

Throws:

Exception

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception