Hadoop FSCK

In Hadoop, fsck stands for “File System Check.” The hadoop fsck command is used to perform a health check on the Hadoop Distributed File System (HDFS) to verify the integrity and status of files and directories stored within it. This command helps administrators identify and resolve issues related to data consistency and replication.

Here is the basic syntax of the hadoop fsck command:

• <path>: The HDFS path to the file or directory you want to check.
• -move: This option moves corrupted files to the /lost+found directory.
• -delete: This option deletes corrupted files.
• -openforwrite: This option checks if the files are open for write.
• -files: This option displays file details.
• -blocks: This option displays block details.
• -locations: This option displays the block locations.
• -racks: This option displays the rack locations.

Typically, you can run the hadoop fsck command without any options to get a summary of the HDFS status, including the total number of blocks, replication levels, and the number of missing and under-replicated blocks. This summary provides an overview of the overall health of your Hadoop cluster.

For example, running the following command will check the health of the entire HDFS:

The output will provide information about the overall health of the HDFS and any issues that may need attention.