HDFS FSCK

In Hadoop Distributed File System (HDFS), the hdfs fsck command is used to check the health and status of the HDFS file system. It provides information about the state of files and blocks stored in HDFS, including the replication factor, the number of live and dead nodes, and any block corruption issues. This command is valuable for administrators and operators to ensure data integrity and reliability within the Hadoop cluster.

Here’s how you can use the hdfs fsck command:

• <path>: This is the HDFS path you want to check. You can specify a specific file or directory in HDFS to check its status.

Options (all optional):

• -files: Displays information about individual files in the specified path, including their block IDs, block sizes, and replication factors.
• -blocks: Provides information about individual blocks, including their block IDs, block sizes, and replication factors.
• -locations: Shows the block replication locations for each block, indicating which DataNodes store each block copy.
• -racks: Displays the rack information for each DataNode.
• -replicaDetails: Provides detailed information about each block’s replicas, including their state (live or dead), storage type, and storage ID.
• -storagepolicies: Shows the storage policies associated with the blocks.

Here’s an example of how you can use the hdfs fsck command to check the health and status of a directory in HDFS: