Did you make changes to your garbage collection?
Could be that you've swamped your nodes and time out due to GC running. > Subject: RE: Region server goes away > Date: Thu, 15 Apr 2010 10:25:45 -0700 > From: ghend...@decarta.com > To: hbase-user@hadoop.apache.org > > After making all the recommended config changes, the only issue I see it > this, in the zookeeper logs. It happens repeatedly. Hbase shell seems to work > fine, running it on same machine as the zookeeper. Any ideas? I reviewed a > thread in the email list, on this topic, but it seemed inconclusive.: > > 2010-04-15 04:14:36,048 WARN > org.apache.zookeeper.server.PrepRequestProcessor: ot exception when > processing sessionid:0x128012c809c0000 type:create cxid:0x4 z > id:0xfffffffffffffffe txntype:unknown n/a > org.apache.zookeeper.KeeperException$NodeExistsException: KeeperErrorCode = > Nod Existsof 0x128012c809c0002 valid:true > at > org.apache.zookeeper.server.PrepRequestProcessor.pRequest(PrepReques > Processor.java:245)87c5a0000 > at > org.apache.zookeeper.server.PrepRequestProcessor.run(PrepRequestProc > ssor.java:114)27fe787c5a3bba > > -----Original Message----- > From: saint....@gmail.com [mailto:saint....@gmail.com] On Behalf Of Stack > Sent: Wednesday, April 14, 2010 8:45 PM > To: hbase-user@hadoop.apache.org > Cc: Paul Mahon; Bill Brune; Shaheen Bahauddin; Rohit Nigam > Subject: Re: Region server goes away > > On Wed, Apr 14, 2010 at 8:27 PM, Geoff Hendrey <ghend...@decarta.com> wrote: > > Hi, > > > > I have posted previously about issues I was having with HDFS when I > > was running HBase and HDFS on the same box both pseudoclustered. Now I > > have two very capable servers. I've setup HDFS with a datanode on each box. > > I've setup the namenode on one box, and the zookeeper and HDFS master > > on the other box. Both boxes are region servers. I am using hadoop > > 20.2 and hbase 20.3. > > What do you have for replication? If two datanodes, you've set it to two > rather than default 3? > > > > > > I have set dfs.datanode.socket.write.timeout to 0 in hbase-site.xml. > > > This is probably not necessary. > > > > I am running a mapreduce job with about 200 concurrent reducers, each > > of which writes into HBase, with 32,000 row flush buffers. > > > Why don't you try with just a few reducers first and then build it up? > See if that works? > > > About 40% > > through the completion of my job, HDFS started showing one of the > > datanodes was dead (the one *not* on the same machine as the namenode). > > > Do you think it dead -- what did a threaddump say? -- or was it just that you > couldn't get into it? Any errors in the datanode logs complaining about > xceiver count or perhaps you need to up the number of handlers? > > > > > I stopped HBase, and magically the datanode came back to life. > > > > Any suggestions on how to increase the robustness? > > > > > > I see errors like this in the datanode's log: > > > > 2010-04-14 12:54:58,692 ERROR > > org.apache.hadoop.hdfs.server.datanode.DataNode: D > > atanodeRegistration(10.241.6.80:50010, > > storageID=DS-642079670-10.241.6.80-50010- > > 1271178858027, infoPort=50075, ipcPort=50020):DataXceiver > > java.net.SocketTimeoutException: 480000 millis timeout while waiting > > for channel > > > I believe this harmless. Its just the DN timing out the socket -- you set > the timeout to 0 in the hbase-site.xml rather than in hdfs-site.xml where it > would have an effect. See HADOOP-3831 for detail. > > > > to be ready for write. ch : java.nio.channels.SocketChannel[connected > > local=/10 > > .241.6.80:50010 remote=/10.241.6.80:48320] > > at > > org.apache.hadoop.net.SocketIOWithTimeout.waitForIO(SocketIOWithTimeo > > ut.java:246) > > at > > org.apache.hadoop.net.SocketOutputStream.waitForWritable(SocketOutput > > Stream.java:159) > > at > > org.apache.hadoop.net.SocketOutputStream.transferToFully(SocketOutput > > Stream.java:198) > > at > > org.apache.hadoop.hdfs.server.datanode.BlockSender.sendChunks(BlockSe > > nder.java:313) > > at > > org.apache.hadoop.hdfs.server.datanode.BlockSender.sendBlock(BlockSen > > der.java:400) > > at > > org.apache.hadoop.hdfs.server.datanode.DataXceiver.readBlock(DataXcei > > ver.java:180) > > at > > org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.ja > > : > > > > > > Here I show the output of 'hadoop dfsadmin -report'. First time it is > > invoked, all is well. Second time, one datanode is dead. Third time, > > the dead datanode has come back to life.: > > > > [had...@dt1 ~]$ hadoop dfsadmin -report Configured Capacity: > > 1277248323584 (1.16 TB) Present Capacity: 1208326105528 (1.1 TB) DFS > > Remaining: 1056438108160 (983.88 GB) DFS Used: 151887997368 (141.46 > > GB) DFS Used%: 12.57% Under replicated blocks: 3479 Blocks with > > corrupt replicas: 0 Missing blocks: 0 > > > > ------------------------------------------------- > > Datanodes available: 2 (2 total, 0 dead) > > > > Name: 10.241.6.79:50010 > > Decommission Status : Normal > > Configured Capacity: 643733970944 (599.52 GB) DFS Used: 75694104268 > > (70.5 GB) Non DFS Used: 35150238004 (32.74 GB) DFS Remaining: > > 532889628672(496.29 GB) DFS Used%: 11.76% DFS Remaining%: 82.78% Last > > contact: Wed Apr 14 11:20:59 PDT 2010 > > > > > > Yeah, my guess as per above is that the reporting client couldn't get on to > the datanode because handlers were full or xceivers exceeded. > > Let us know how it goes. > St.Ack > > > > Name: 10.241.6.80:50010 > > Decommission Status : Normal > > Configured Capacity: 633514352640 (590.01 GB) DFS Used: 76193893100 > > (70.96 GB) Non DFS Used: 33771980052 (31.45 GB) DFS Remaining: > > 523548479488(487.59 GB) DFS Used%: 12.03% DFS Remaining%: 82.64% Last > > contact: Wed Apr 14 11:14:37 PDT 2010 > > > > > > [had...@dt1 ~]$ hadoop dfsadmin -report Configured Capacity: > > 643733970944 (599.52 GB) Present Capacity: 609294929920 (567.45 GB) > > DFS Remaining: 532876144640 (496.28 GB) DFS Used: 76418785280 (71.17 > > GB) DFS Used%: 12.54% Under replicated blocks: 3247 Blocks with > > corrupt replicas: 0 Missing blocks: 0 > > > > ------------------------------------------------- > > Datanodes available: 1 (2 total, 1 dead) > > > > Name: 10.241.6.79:50010 > > Decommission Status : Normal > > Configured Capacity: 643733970944 (599.52 GB) DFS Used: 76418785280 > > (71.17 GB) Non DFS Used: 34439041024 (32.07 GB) DFS Remaining: > > 532876144640(496.28 GB) DFS Used%: 11.87% DFS Remaining%: 82.78% Last > > contact: Wed Apr 14 11:28:38 PDT 2010 > > > > > > Name: 10.241.6.80:50010 > > Decommission Status : Normal > > Configured Capacity: 0 (0 KB) > > DFS Used: 0 (0 KB) > > Non DFS Used: 0 (0 KB) > > DFS Remaining: 0(0 KB) > > DFS Used%: 100% > > DFS Remaining%: 0% > > Last contact: Wed Apr 14 11:14:37 PDT 2010 > > > > > > [had...@dt1 ~]$ hadoop dfsadmin -report Configured Capacity: > > 1277248323584 (1.16 TB) Present Capacity: 1210726427080 (1.1 TB) DFS > > Remaining: 1055440003072 (982.96 GB) DFS Used: 155286424008 (144.62 > > GB) DFS Used%: 12.83% Under replicated blocks: 3338 Blocks with > > corrupt replicas: 0 Missing blocks: 0 > > > > ------------------------------------------------- > > Datanodes available: 2 (2 total, 0 dead) > > > > Name: 10.241.6.79:50010 > > Decommission Status : Normal > > Configured Capacity: 643733970944 (599.52 GB) DFS Used: 77775145981 > > (72.43 GB) Non DFS Used: 33086850051 (30.81 GB) DFS Remaining: > > 532871974912(496.28 GB) DFS Used%: 12.08% DFS Remaining%: 82.78% Last > > contact: Wed Apr 14 11:29:44 PDT 2010 > > > > > > Name: 10.241.6.80:50010 > > Decommission Status : Normal > > Configured Capacity: 633514352640 (590.01 GB) DFS Used: 77511278027 > > (72.19 GB) Non DFS Used: 33435046453 (31.14 GB) DFS Remaining: > > 522568028160(486.68 GB) DFS Used%: 12.24% DFS Remaining%: 82.49% Last > > contact: Wed Apr 14 11:29:44 PDT 2010 > > > > > > > > _________________________________________________________________ Hotmail is redefining busy with tools for the New Busy. 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