[HDFS-6231] DFSClient hangs infinitely if using hedged reads and all eligible datanodes die.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.0, 3.0.0-alpha1
• Fix Version/s: 2.4.1
• Component/s: hdfs-client
• Target Version/s: 2.4.1
• Hadoop Flags: Reviewed
• Assignee: Chris Nauroth
• Reporter: Chris Nauroth
• Created: 10/Apr/14 20:18
• Updated: 12/May/16 18:18
• Resolved: 11/Apr/14 04:08

Description

When using hedged reads, and all eligible datanodes for the read get flagged as dead or ignored, then the client is supposed to refetch block locations from the NameNode to retry the read. Instead, we've seen that the client can hang indefinitely.

Issue Links

• duplicates: HDFS-6494 In some case, the hedged read will lead to client infinite wait.
• is related to: HDFS-5776 Support 'hedged' reads in DFSClient
• relates to: HDFS-6494 In some case, the hedged read will lead to client infinite wait.