Hi everyone, (apologies if this gets posted on the list twice for some reason, my first attempt was denied as "suspected spam")
I ran a job last night with Hadoop 0.18.0 on EC2, using the standard small AMI. The job was producing gzipped output, otherwise I haven't changed the configuration. The final reduce steps failed with this error that I haven't seem before: 2008-10-01 05:02:39,810 WARN org.apache.hadoop.mapred.ReduceTask: attempt_200809301822_0005_r_000001_0 Merging of the local FS files threw an exception: java.io.IOException: java.io.IOException: Rec# 289050: Negative value-length: -96 at org.apache.hadoop.mapred.IFile$Reader.next(IFile.java:331) at org.apache.hadoop.mapred.Merger$Segment.next(Merger.java:134) at org.apache.hadoop.mapred.Merger$MergeQueue.adjustPriorityQueue(Merger.java:225) at org.apache.hadoop.mapred.Merger$MergeQueue.next(Merger.java:242) at org.apache.hadoop.mapred.Merger.writeFile(Merger.java:83) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$LocalFSMerger.run(ReduceTask.java:2021) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$LocalFSMerger.run(ReduceTask.java:2025) 2008-10-01 05:02:44,131 WARN org.apache.hadoop.mapred.TaskTracker: Error running child java.io.IOException: attempt_200809301822_0005_r_000001_0The reduce copier failed at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:255) at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:2209) When I try to download the data from HDFS I get a "Found checksum error" warning message. Any ideas what could be the cause? Would upgrading to 0.18.1 solve it? Thanks, / Per