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