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
>
>
>
>
