Yes your .205 release should have it. It should fix your issue! On Fri, Dec 30, 2011 at 6:24 PM, Markus Jelsma <[email protected]> wrote: > Hi, (didn't reply to list before) > >> Does your DN log show up any form of errors when you run into this? > > Actually, i looked checked again to be sure and noticed errors that i didn't > notice before: > > 2011-12-29 19:51:01,799 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: > DatanodeRegistration(141.105.120.152:50010, > storageID=DS-454617998-141.105.120.152-50010-1324646606851, infoPort=50075, > ipcPort=50020):DataXceiver > java.io.IOException: xceiverCount 258 exceeds the limit of concurrent xcievers > 256 > at > org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:92) > at java.lang.Thread.run(Thread.java:662) > > but also this one: > > 2011-12-29 19:51:00,675 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: > DatanodeRegistration(141.105.120.152:50010, > storageID=DS-454617998-141.105.120.152-50010-1324646606851, infoPort=50075, > ipcPort=50020):DataXceiver > java.io.EOFException > at java.io.DataInputStream.readShort(DataInputStream.java:298) > at > org.apache.hadoop.hdfs.server.datanode.DataXceiver.writeBlock(DataXceiver.java:351) > at > org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:107) > at java.lang.Thread.run(Thread.java:662) > > >> This happens with just two jobs reading how many files? And how many >> DNs are these spread across? > > One file, 15 parts spread across five machines. > >> >> I'm thinking its probably something to do with your ulimits for the >> running DN processes, but I can't say for sure without taking a look >> at the logs. > > Ulimits for open files is set to 16k for all machines. > >> >> Some other stuff I can think of, a little blindly: >> - What's your dfs.datanode.max.xcievers settings? > > I don't know. I increased it for a 0.22.0 test cluster but this is 0.20.205.0 > and i haven't seen that configuration directive in the manual for this > version. At least not in the hdfs-, core or mapred-default files. > >> - Can you ensure 'hadoop classpath' on all nodes reflects the same >> output, and no accidental jar mixups? > > They are identical. All machines were installed and configured automatically > and looking at it i don't see any differences. > > Is there such a max.xceivers setting in the 0.20.x branch? Judging from the > exception it might be that's the problem. > > Thanks! > > > > > >> Does your DN log show up any form of errors when you run into this? >> This happens with just two jobs reading how many files? And how many >> DNs are these spread across? >> >> I'm thinking its probably something to do with your ulimits for the >> running DN processes, but I can't say for sure without taking a look >> at the logs. >> >> Some other stuff I can think of, a little blindly: >> - What's your dfs.datanode.max.xcievers settings? >> - Can you ensure 'hadoop classpath' on all nodes reflects the same >> output, and no accidental jar mixups? >> >> On Thu, Dec 29, 2011 at 11:48 PM, Markus Jelsma >> >> <[email protected]> wrote: >> > We just reproduced it (somehow) by running jobs concurrently reading the >> > same data. Two out of three similar jobs died early in the map phase >> > with Could not obtain block errors, one finished completely. >> > >> > java.io.IOException: Could not obtain block: blk_119146860335302651_13067 >> > file=/user/systems/crawl/crawldb/current/part-00000/data >> > at >> > org.apache.hadoop.hdfs.DFSClient$DFSInputStream.chooseDataNode(DFSClient. >> > java:2093) at >> > org.apache.hadoop.hdfs.DFSClient$DFSInputStream.blockSeekTo(DFSClient.jav >> > a:1897) at >> > org.apache.hadoop.hdfs.DFSClient$DFSInputStream.read(DFSClient.java:2048) >> > at java.io.DataInputStream.readFully(DataInputStream.java:178) >> > at >> > org.apache.hadoop.io.DataOutputBuffer$Buffer.write(DataOutputBuffer.java: >> > 63) at >> > org.apache.hadoop.io.DataOutputBuffer.write(DataOutputBuffer.java:101) >> > at org.apache.hadoop.io.SequenceFile$Reader.next(SequenceFile.java:1937) >> > at org.apache.hadoop.io.SequenceFile$Reader.next(SequenceFile.java:2069) >> > at >> > org.apache.hadoop.mapreduce.lib.input.SequenceFileRecordReader.nextKeyVal >> > ue(SequenceFileRecordReader.java:68) at >> > org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(Map >> > Task.java:532) at >> > org.apache.hadoop.mapreduce.MapContext.nextKeyValue(MapContext.java:67) >> > at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:143) at >> > org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764) at >> > org.apache.hadoop.mapred.MapTask.run(MapTask.java:370) at >> > org.apache.hadoop.mapred.Child$4.run(Child.java:255) >> > at java.security.AccessController.doPrivileged(Native Method) >> > at javax.security.auth.Subject.doAs(Subject.java:396) >> > at >> > org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation >> > .java:1059) at org.apache.hadoop.mapred.Child.main(Child.java:249) >> > >> > Another job (different but reading the same data) finished the map phase >> > but died partially (half of the reducers) and completely frooze. >> > >> > 2011-12-29 18:07:58,899 INFO org.apache.hadoop.hdfs.DFSClient: Exception >> > in createBlockOutputStream java.io.EOFException >> > 2011-12-29 18:07:58,899 INFO org.apache.hadoop.hdfs.DFSClient: Abandoning >> > block blk_4748641522370871094_13532 >> > 2011-12-29 18:07:58,900 INFO org.apache.hadoop.hdfs.DFSClient: Excluding >> > datanode 141.105.120.154:50010 >> > 2011-12-29 18:07:58,902 INFO org.apache.hadoop.hdfs.DFSClient: Exception >> > in createBlockOutputStream java.io.EOFException >> > 2011-12-29 18:07:58,902 INFO org.apache.hadoop.hdfs.DFSClient: Abandoning >> > block blk_-1454920600140944030_13532 >> > 2011-12-29 18:07:58,903 INFO org.apache.hadoop.hdfs.DFSClient: Excluding >> > datanode 141.105.120.152:50010 >> > 2011-12-29 18:07:58,907 INFO org.apache.hadoop.hdfs.DFSClient: Exception >> > in createBlockOutputStream java.io.IOException: Bad connect ack with >> > firstBadLink as 141.105.120.153:50010 >> > 2011-12-29 18:07:58,907 INFO org.apache.hadoop.hdfs.DFSClient: Abandoning >> > block blk_3551418605384221738_13532 >> > 2011-12-29 18:07:58,908 INFO org.apache.hadoop.hdfs.DFSClient: Excluding >> > datanode 141.105.120.153:50010 >> > 2011-12-29 18:07:58,910 INFO org.apache.hadoop.hdfs.DFSClient: Exception >> > in createBlockOutputStream java.io.EOFException >> > 2011-12-29 18:07:58,910 INFO org.apache.hadoop.hdfs.DFSClient: Abandoning >> > block blk_-1826030182013954555_13532 >> > 2011-12-29 18:07:58,911 INFO org.apache.hadoop.hdfs.DFSClient: Excluding >> > datanode 141.105.120.150:50010 >> > 2011-12-29 18:07:58,911 WARN org.apache.hadoop.hdfs.DFSClient: >> > DataStreamer Exception: java.io.IOException: Unable to create new block. >> > at >> > org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.nextBlockOutputStream(DF >> > SClient.java:3213) at >> > org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.access$2300(DFSClient.ja >> > va:2406) at >> > org.apache.hadoop.hdfs.DFSClient$DFSOutputStream$DataStreamer.run(DFSClie >> > nt.java:2646) >> > >> > 2011-12-29 18:07:58,912 WARN org.apache.hadoop.hdfs.DFSClient: Error >> > Recovery for block blk_-1826030182013954555_13532 bad datanode[0] nodes >> > == null 2011-12-29 18:07:58,912 WARN org.apache.hadoop.hdfs.DFSClient: >> > Could not get block locations. Source file "/user/systems/generate- >> > temp-1325180944829/_temporary/_attempt_201112290956_0012_r_000004_0/fetch >> > list-13/part-00004" - Aborting... >> > 2011-12-29 18:07:59,049 INFO org.apache.hadoop.mapred.TaskLogsTruncater: >> > Initializing logs' truncater with mapRetainSize=-1 and >> > reduceRetainSize=-1 2011-12-29 18:07:59,062 WARN >> > org.apache.hadoop.mapred.Child: Error running child >> > java.io.EOFException >> > at java.io.DataInputStream.readShort(DataInputStream.java:298) >> > at >> > org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.createBlockOutputStream( >> > DFSClient.java:3272) at >> > org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.nextBlockOutputStream(DF >> > SClient.java:3196) at >> > org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.access$2300(DFSClient.ja >> > va:2406) at >> > org.apache.hadoop.hdfs.DFSClient$DFSOutputStream$DataStreamer.run(DFSClie >> > nt.java:2646) 2011-12-29 18:07:59,064 INFO org.apache.hadoop.mapred.Task: >> > Runnning cleanup for the task >> > >> > It smells like the datanodes in 20.205.0 don't deal well with concurrent >> > jobs, especially handling the same data. >> > >> > Is there any advice for this? Again, this does not happen on 20.203.0. >> > Many thanks >> > >> >> I should add that the failing tasks that ran concurrently all read the >> >> same map files from HDFS. >> >> >> >> > Hi, >> >> > >> >> > We just ran run large scale Apache Nutch jobs in our evaluation of >> >> > 20.205.0 and they all failed. Some of these jobs ran concurrently with >> >> > the fair scheduler enabled. These were simple jobs consuming little >> >> > RAM. I double checked and there were certainly no RAM issues. >> >> > >> >> > All jobs failed and most tasks had a less than descriptive message. A >> >> > few told they dealt with I/O errors reading task output. However, the >> >> > data the read is fine. When we ran the same jobs manually (and some >> >> > concurrently) some did fine and others died for with I/O errors >> >> > reading task output again! >> >> > >> >> > The heap allocation for the reducers is not high but no OOM's were >> >> > reported. Besides the occasional I/O error, which i think is strange >> >> > enough, most tasks did not write anything to the logs that i can link >> >> > to this problem. >> >> > >> >> > We do not see this happening on our 20.203.0 cluster although >> >> > resources and settings are different. 205 is a new high-end cluster >> >> > with similar conservative settings but only more mappers/reducers per >> >> > node. Resource settings are almost identical. The 203 cluster has >> >> > three times as many machines so also more open file descriptors and >> >> > threads. >> >> > >> >> > Any thoughts to share? >> >> > Thanks,
-- Harsh J
