Nope, that didn't seem to help. On Sun, Sep 26, 2010 at 1:00 AM, Bradford Stephens <[email protected]> wrote: > I'm going to try running it on high-RAM boxes with -Xmx4096m or so, > see if that helps. > > On Sun, Sep 26, 2010 at 12:55 AM, Bradford Stephens > <[email protected]> wrote: >> Greetings, >> >> I'm running into a brain-numbing problem on Elastic MapReduce. I'm >> running a decent-size task (22,000 mappers, a ton of GZipped input >> blocks, ~1TB of data) on 40 c1.xlarge nodes (7 gb RAM, ~8 "cores"). >> >> I get failures randomly --- sometimes at the end of my 6-step process, >> sometimes at the first reducer phase, sometimes in the mapper. It >> seems to fail in multiple areas. Mostly in the reducers. Any ideas? >> >> Here's the settings I've changed: >> -Xmx400m >> 6 max mappers >> 1 max reducer >> 1GB swap partition >> mapred.job.reuse.jvm.num.tasks=50 >> mapred.reduce.parallel.copies=3 >> >> >> java.lang.OutOfMemoryError: GC overhead limit exceeded >> at java.nio.CharBuffer.wrap(CharBuffer.java:350) >> at java.nio.CharBuffer.wrap(CharBuffer.java:373) >> at java.lang.StringCoding$StringDecoder.decode(StringCoding.java:138) >> at java.lang.StringCoding.decode(StringCoding.java:173) >> at java.lang.String.(String.java:443) >> at java.lang.String.(String.java:515) >> at >> org.apache.hadoop.io.WritableUtils.readString(WritableUtils.java:116) >> at >> cascading.tuple.TupleInputStream.readString(TupleInputStream.java:144) >> at >> cascading.tuple.TupleInputStream.readType(TupleInputStream.java:154) >> at >> cascading.tuple.TupleInputStream.getNextElement(TupleInputStream.java:101) >> at >> cascading.tuple.hadoop.TupleElementComparator.compare(TupleElementComparator.java:75) >> at >> cascading.tuple.hadoop.TupleElementComparator.compare(TupleElementComparator.java:33) >> at >> cascading.tuple.hadoop.DelegatingTupleElementComparator.compare(DelegatingTupleElementComparator.java:74) >> at >> cascading.tuple.hadoop.DelegatingTupleElementComparator.compare(DelegatingTupleElementComparator.java:34) >> at >> cascading.tuple.hadoop.DeserializerComparator.compareTuples(DeserializerComparator.java:142) >> at >> cascading.tuple.hadoop.GroupingSortingComparator.compare(GroupingSortingComparator.java:55) >> at >> org.apache.hadoop.mapred.Merger$MergeQueue.lessThan(Merger.java:373) >> at >> org.apache.hadoop.util.PriorityQueue.downHeap(PriorityQueue.java:136) >> at >> org.apache.hadoop.util.PriorityQueue.adjustTop(PriorityQueue.java:103) >> at >> org.apache.hadoop.mapred.Merger$MergeQueue.adjustPriorityQueue(Merger.java:335) >> at org.apache.hadoop.mapred.Merger$MergeQueue.next(Merger.java:350) >> at org.apache.hadoop.mapred.Merger.writeFile(Merger.java:156) >> at >> org.apache.hadoop.mapred.ReduceTask$ReduceCopier$InMemFSMergeThread.doInMemMerge(ReduceTask.java:2645) >> at >> org.apache.hadoop.mapred.ReduceTask$ReduceCopier$InMemFSMergeThread.run(ReduceTask.java:2586) >> >> -- >> Bradford Stephens, >> Founder, Drawn to Scale >> drawntoscalehq.com >> 727.697.7528 >> >> http://www.drawntoscalehq.com -- The intuitive, cloud-scale data >> solution. Process, store, query, search, and serve all your data. >> >> http://www.roadtofailure.com -- The Fringes of Scalability, Social >> Media, and Computer Science >> > > > > -- > Bradford Stephens, > Founder, Drawn to Scale > drawntoscalehq.com > 727.697.7528 > > http://www.drawntoscalehq.com -- The intuitive, cloud-scale data > solution. Process, store, query, search, and serve all your data. > > http://www.roadtofailure.com -- The Fringes of Scalability, Social > Media, and Computer Science >
-- Bradford Stephens, Founder, Drawn to Scale drawntoscalehq.com 727.697.7528 http://www.drawntoscalehq.com -- The intuitive, cloud-scale data solution. Process, store, query, search, and serve all your data. http://www.roadtofailure.com -- The Fringes of Scalability, Social Media, and Computer Science
