[HBASE-24919] A tool to rewrite corrupted HFiles

• Type: Brainstorming
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Component/s: hbase-operator-tools
• Assignee: Unassigned
• Reporter: Andrey Elenskiy
• Created: 20/Aug/20 20:20
• Updated: 21/Aug/20 07:17
• Resolved: 21/Aug/20 07:17

Description

Typically I have been dealing with corrupted HFiles (due to loss of hdfs blocks) by just removing them. However, It always seemed wasteful to throw away the entire HFile (which can be hundreds of gigabytes), just because one hdfs block is missing (128MB).

I think there's a possibility for a tool that can rewrite an HFile by skipping corrupted blocks.

There can be multiple types of issues with hdfs blocks but any of them can be treated as if the block doesn't exist:
1. All the replicas can be lost
2. The block can be corrupted due to some bug in hdfs (I've recently run into HDFS-15186 by experimenting with EC).

At the simplest the tool can be a local mapreduce job (mapper only) with a custom HFile reader input that can seek to next DATABLK to skip corrupted hdfs blocks.