[HDFS-1787] "Not enough xcievers" error should propagate to client

• Type: Improvement
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.23.0
• Component/s: datanode
• Labels: BB2015-05-TBR newbie
• Release Note: This changes the DataTransferProtocol to return a new error code when a max tranfers exceeded messages is encountered.
• Assignee: Unassigned
• Reporter: Todd Lipcon
• Created: 25/Mar/11 18:40
• Updated: 06/May/15 03:27

Description

We find that users often run into the default transceiver limits in the DN. Putting aside the inherent issues with xceiver threads, it would be nice if the "xceiver limit exceeded" error propagated to the client. Currently, clients simply see an EOFException which is hard to interpret, and have to go slogging through DN logs to find the underlying issue.

The data transfer protocol should be extended to either have a special error code for "not enough xceivers" or should have some error code for generic errors with which a string can be attached and propagated.

Issue Links

• depends upon: HADOOP-7301 FSDataInputStream should expose a getWrappedStream method