[HDFS-1346] DFSClient receives out of order packet ack

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20-append
• Fix Version/s: 0.20-append, 0.20.205.0
• Component/s: datanode, hdfs-client
• Hadoop Flags: Reviewed
• Assignee: Hairong Kuang
• Reporter: Hairong Kuang
• Created: 18/Aug/10 18:18
• Updated: 19/Oct/11 00:26
• Resolved: 27/Sep/10 18:14

Description

When running 0.20 patched with HDFS-101, we sometimes see an error as follow:
WARN hdfs.DFSClient: DFSOutputStream ResponseProcessor exception for block blk_-2871223654872350746_21421120java.io.IOException: Responseprocessor: Expecting seq
no for block blk_-2871223654872350746_21421120 10280 but received 10281
at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream$ResponseProcessor.run(DFSClient.java:2570)

This indicates that DFS client expects an ack for packet N, but receives an ack for packet N+1.

Issue Links

• is related to: HDFS-101 DFS write pipeline : DFSClient sometimes does not detect second datanode failure