[HDFS-6682] Add a metric to expose the timestamp of the oldest under-replicated block

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Labels: metrics
• Assignee: Akira Ajisaka
• Reporter: Akira Ajisaka
• Created: 15/Jul/14 08:16
• Updated: 17/Oct/16 22:25
• Resolved: 17/Oct/16 02:41

Description

In the following case, the data in the HDFS is lost and a client needs to put the same file again.

1. A Client puts a file to HDFS
2. A DataNode crashes before replicating a block of the file to other DataNodes

I propose a metric to expose the timestamp of the oldest under-replicated/corrupt block. That way client can know what file to retain for the re-try.

Issue Links

• is related to: HDFS-10341 Add a metric to expose the timeout number of pending replication blocks
• relates to: HDFS-11024 Add rate metrics for block recovery work