[HDFS-2512] Add textual error message to data transfer protocol responses

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.0
• Fix Version/s: 0.23.0
• Component/s: datanode, hdfs-client
• Hadoop Flags: Reviewed
• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 29/Oct/11 00:19
• Updated: 15/Nov/11 00:52
• Resolved: 31/Oct/11 21:54

Description

Currently, the error response code from the DN has very little extra info. I had a situation the other day where the balancer was failing to move blocks, but just reported back "error moving block", which didn't help much. We can easily add a "message" field to OpBlockResponseProto to communicate back the underlying issue (in this case, it was thread quota exceeded)