Hi Ted, Nicholas,
Thanks for the comments. We found some issues with lease recovery and I
patched HBASE 8354 to ensure we don't see data loss. Could you please look
at HDFS 4721 and HBASE 8389 ?
Thanks
Varun
On Sat, Apr 20, 2013 at 10:52 AM, Varun Sharma <va...@pinterest.com> wrote:
> The important thing to note is the block for this rogue WAL is
> UNDER_RECOVERY state. I have repeatedly asked HDFS dev if the stale node
> thing kicks in correctly for UNDER_RECOVERY blocks but failed.
>
>
> On Sat, Apr 20, 2013 at 10:47 AM, Varun Sharma <va...@pinterest.com>wrote:
>
>> Hi Nicholas,
>>
>> Regarding the following, I think this is not a recovery - the file below
>> is an HFIle and is being accessed on a get request. On this cluster, I
>> don't have block locality. I see these exceptions for a while and then they
>> are gone, which means the stale node thing kicks in.
>>
>> 2013-04-19 00:27:28,432 WARN org.apache.hadoop.hdfs.DFSClient: Failed to
>> connect to /10.156.194.94:50010 for file
>> /hbase/feeds/1479495ad2a02dceb41f093ebc29fe4f/home/
>> 02f639bb43944d4ba9abcf58287831c0
>> for block
>>
>> This is the real bummer. The stale datanode is 1st even 90 seconds
>> afterwards.
>>
>> *2013-04-19 00:28:35*,777 WARN
>> org.apache.hadoop.hbase.regionserver.SplitLogWorker: log splitting of
>> hdfs://
>> ec2-107-20-237-30.compute-1.amazonaws.com/hbase/.logs/ip-10-156-194-94.ec2.internal,60020,1366323217601-splitting/ip-10-156-194-94.ec2.internal%2C60020%2C1366323217601.1366331156141failed,
>> returning error
>> java.io.IOException: Cannot obtain block length for
>> LocatedBlock{BP-696828882-10.168.7.226-1364886167971:blk_-5723958680970112840_174056;
>> getBlockSize()=0; corrupt=false; offset=0; locs=*[10.156.194.94:50010,
>> 10.156.192.106:50010, 10.156.195.38:50010]}*
>> >---at
>> org.apache.hadoop.hdfs.DFSInputStream.readBlockLength(DFSInputStream.java:238)
>> >---at
>> org.apache.hadoop.hdfs.DFSInputStream.fetchLocatedBlocksAndGetLastBlockLength(DFSInputStream.java:182)
>> >---at
>> org.apache.hadoop.hdfs.DFSInputStream.openInfo(DFSInputStream.java:124)
>> >---at
>> org.apache.hadoop.hdfs.DFSInputStream.<init>(DFSInputStream.java:117)
>> >---at org.apache.hadoop.hdfs.DFSClient.open(DFSClient.java:1080)
>> >---at
>> org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:245)
>> >---at
>> org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:78)
>> >---at
>> org.apache.hadoop.io.SequenceFile$Reader.openFile(SequenceFile.java:1787)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader$WALReader.openFile(SequenceFileLogReader.java:62)
>> >---at
>> org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1707)
>> >---at
>> org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1728)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader$WALReader.<init>(SequenceFileLogReader.java:55)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader.init(SequenceFileLogReader.java:175)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.HLog.getReader(HLog.java:717)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.getReader(HLogSplitter.java:821)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.getReader(HLogSplitter.java:734)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.splitLogFile(HLogSplitter.java:381)
>> >---at
>> org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.splitLogFile(HLogSplitter.java:348)
>> >---at
>> org.apache.hadoop.hbase.regionserver.SplitLogWorker$1.exec(SplitLogWorker.java:111)
>> >---at
>> org.apache.hadoop.hbase.regionserver.SplitLogWorker.grabTask(SplitLogWorker.java:264)
>> >---at
>> org.apache.hadoop.hbase.regionserver.SplitLogWorker.taskLoop(SplitLogWorker.java:195)
>> >---at
>> org.apache.hadoop.hbase.regionserver.SplitLogWorker.run(SplitLogWorker.java:163)
>> >---at java.lang.Thread.run(Thread.java:662)
>>
>>
>>
>> On Sat, Apr 20, 2013 at 1:16 AM, Nicolas Liochon <nkey...@gmail.com>wrote:
>>
>>> Hi,
>>>
>>> I looked at it again with a fresh eye. As Varun was saying, the root
>>> cause
>>> is the wrong order of the block locations.
>>>
>>> The root cause of the root cause is actually simple: HBASE started the
>>> recovery while the node was not yet stale from an HDFS pov.
>>>
>>> Varun mentioned this timing:
>>> Lost Beat: 27:30
>>> Became stale: 27:50 - * this is a guess and reverse engineered (stale
>>> timeout 20 seconds)
>>> Became dead: 37:51
>>>
>>> But the recovery started at 27:13 (15 seconds before we have this log
>>> line)
>>> 2013-04-19 00:27:28,432 WARN org.apache.hadoop.hdfs.DFSClient: Failed to
>>> connect to /10.156.194.94:50010 for file
>>>
>>> /hbase/feeds/1479495ad2a02dceb41f093ebc29fe4f/home/02f639bb43944d4ba9abcf58287831c0
>>> for block
>>>
>>> BP-696828882-10.168.7.226-1364886167971:blk_-5977178030490858298_99853:java.net.SocketTimeoutException:
>>> 15000 millis timeout while waiting for channel to be ready for connect.
>>> ch
>>> : java.nio.channels.SocketChannel[connection-pending remote=/
>>> 10.156.194.94:50010]
>>>
>>> So when we took the blocks from the NN, the datanode was not stale, so
>>> you
>>> have the wrong (random) order.
>>>
>>> ZooKeeper can expire a session before the timeout. I don't what why it
>>> does
>>> this in this case, but I don't consider it as a ZK bug: if ZK knows that
>>> a
>>> node is dead, it's its role to expire the session. There is something
>>> more
>>> fishy: we started the recovery while the datanode was still responding to
>>> heartbeat. I don't know why. Maybe the OS has been able to kill 15 the RS
>>> before vanishing away.
>>>
>>> Anyway, we then have an exception when we try to connect, because the RS
>>> does not have a TCP connection to this datanode. And this is retried many
>>> times.
>>>
>>> You would not have this with trunk, because HBASE-6435 reorders the
>>> blocks
>>> inside the client, using an information not available to the NN,
>>> excluding
>>> the datanode of the region server under recovery.
>>>
>>> Some conclusions:
>>> - we should likely backport hbase-6435 to 0.94.
>>> - I will revive HDFS-3706 and HDFS-3705 (the non hacky way to get
>>> hbase-6435).
>>> - There are some stuff that could be better in HDFS. I will see.
>>> - I'm worried by the SocketTimeoutException. We should get NoRouteToHost
>>> at a moment, and we don't. That's also why it takes ages. I think it's an
>>> AWS thing, but it brings to issue: it's slow, and, in HBase, you don't
>>> know
>>> if the operation could have been executed or not, so it adds complexity
>>> to
>>> some scenarios. If someone with enough network and AWS knowledge could
>>> clarify this point it would be great.
>>>
>>> Cheers,
>>>
>>> Nicolas
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Fri, Apr 19, 2013 at 10:10 PM, Varun Sharma <va...@pinterest.com>
>>> wrote:
>>>
>>> > This is 0.94.3 hbase...
>>> >
>>> >
>>> > On Fri, Apr 19, 2013 at 1:09 PM, Varun Sharma <va...@pinterest.com>
>>> wrote:
>>> >
>>> > > Hi Ted,
>>> > >
>>> > > I had a long offline discussion with nicholas on this. Looks like the
>>> > last
>>> > > block which was still being written too, took an enormous time to
>>> > recover.
>>> > > Here's what happened.
>>> > > a) Master split tasks and region servers process them
>>> > > b) Region server tries to recover lease for each WAL log - most
>>> cases are
>>> > > noop since they are already rolled over/finalized
>>> > > c) The last file lease recovery takes some time since the crashing
>>> server
>>> > > was writing to it and had a lease on it - but basically we have the
>>> > lease 1
>>> > > minute after the server was lost
>>> > > d) Now we start the recovery for this but we end up hitting the stale
>>> > data
>>> > > node which is puzzling.
>>> > >
>>> > > It seems that we did not hit the stale datanode when we were trying
>>> to
>>> > > recover the finalized WAL blocks with trivial lease recovery.
>>> However,
>>> > for
>>> > > the final block, we hit the stale datanode. Any clue why this might
>>> be
>>> > > happening ?
>>> > >
>>> > > Varun
>>> > >
>>> > >
>>> > > On Fri, Apr 19, 2013 at 10:40 AM, Ted Yu <yuzhih...@gmail.com>
>>> wrote:
>>> > >
>>> > >> Can you show snippet from DN log which mentioned UNDER_RECOVERY ?
>>> > >>
>>> > >> Here is the criteria for stale node checking to kick in (from
>>> > >>
>>> > >>
>>> >
>>> https://issues.apache.org/jira/secure/attachment/12544897/HDFS-3703-trunk-read-only.patch
>>> > >> ):
>>> > >>
>>> > >> + * Check if the datanode is in stale state. Here if
>>> > >> + * the namenode has not received heartbeat msg from a
>>> > >> + * datanode for more than staleInterval (default value is
>>> > >> + * {@link
>>> > >> DFSConfigKeys#DFS_NAMENODE_STALE_DATANODE_INTERVAL_MILLI_DEFAULT}),
>>> > >> + * the datanode will be treated as stale node.
>>> > >>
>>> > >>
>>> > >> On Fri, Apr 19, 2013 at 10:28 AM, Varun Sharma <va...@pinterest.com
>>> >
>>> > >> wrote:
>>> > >>
>>> > >> > Is there a place to upload these logs ?
>>> > >> >
>>> > >> >
>>> > >> > On Fri, Apr 19, 2013 at 10:25 AM, Varun Sharma <
>>> va...@pinterest.com>
>>> > >> > wrote:
>>> > >> >
>>> > >> > > Hi Nicholas,
>>> > >> > >
>>> > >> > > Attached are the namenode, dn logs (of one of the healthy
>>> replicas
>>> > of
>>> > >> the
>>> > >> > > WAL block) and the rs logs which got stuch doing the log split.
>>> > Action
>>> > >> > > begins at 2013-04-19 00:27*.
>>> > >> > >
>>> > >> > > Also, the rogue block is 5723958680970112840_174056. Its very
>>> > >> interesting
>>> > >> > > to trace this guy through the HDFS logs (dn and nn).
>>> > >> > >
>>> > >> > > Btw, do you know what the UNDER_RECOVERY stage is for, in HDFS ?
>>> > Also
>>> > >> > does
>>> > >> > > the stale node stuff kick in for that state ?
>>> > >> > >
>>> > >> > > Thanks
>>> > >> > > Varun
>>> > >> > >
>>> > >> > >
>>> > >> > > On Fri, Apr 19, 2013 at 4:00 AM, Nicolas Liochon <
>>> nkey...@gmail.com
>>> > >> > >wrote:
>>> > >> > >
>>> > >> > >> Thanks for the detailed scenario and analysis. I'm going to
>>> have a
>>> > >> look.
>>> > >> > >> I can't access the logs (
>>> ec2-107-20-237-30.compute-1.amazonaws.com
>>> > >> > >> timeouts), could you please send them directly to me?
>>> > >> > >>
>>> > >> > >> Thanks,
>>> > >> > >>
>>> > >> > >> Nicolas
>>> > >> > >>
>>> > >> > >>
>>> > >> > >> On Fri, Apr 19, 2013 at 12:46 PM, Varun Sharma <
>>> > va...@pinterest.com>
>>> > >> > >> wrote:
>>> > >> > >>
>>> > >> > >> > Hi Nicholas,
>>> > >> > >> >
>>> > >> > >> > Here is the failure scenario, I have dug up the logs.
>>> > >> > >> >
>>> > >> > >> > A machine fails and stops accepting/transmitting traffic. The
>>> > >> HMaster
>>> > >> > >> > starts the distributed split for 13 tasks. There are 12
>>> region
>>> > >> > servers.
>>> > >> > >> 12
>>> > >> > >> > tasks succeed but the 13th one takes a looong time.
>>> > >> > >> >
>>> > >> > >> > Zookeeper timeout is set to 30 seconds. Stale node timeout
>>> is 20
>>> > >> > >> seconds.
>>> > >> > >> > Both patches are there.
>>> > >> > >> >
>>> > >> > >> > a) Machine fails around 27:30
>>> > >> > >> > b) Master starts the split around 27:40 and submits the
>>> tasks.
>>> > The
>>> > >> one
>>> > >> > >> task
>>> > >> > >> > which fails seems to be the one which contains the WAL being
>>> > >> currently
>>> > >> > >> > written to:
>>> > >> > >> >
>>> > >> > >> > 2013-04-19 00:27:44,325 INFO
>>> > >> > >> > org.apache.hadoop.hbase.regionserver.wal.HLogSplitter:
>>> Splitting
>>> > >> hlog:
>>> > >> > >> > hdfs://
>>> > >> > >> >
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> ec2-107-20-237-30.compute-1.amazonaws.com/hbase/.logs/ip-10-156-194-94.ec2.internal,60020,1366323217601-splitting/ip-10-156-194-94.ec2.internal%2C60020%2C1366323217601.1366331156141
>>> > >> > >> > ,
>>> > >> > >> > length=0
>>> > >> > >> >
>>> > >> > >> > Basically this region server picks up the task but finds the
>>> > >> length of
>>> > >> > >> this
>>> > >> > >> > file to be 0 and drops. This happens again
>>> > >> > >> >
>>> > >> > >> > c) Finally another region server picks up the task but it
>>> ends up
>>> > >> > going
>>> > >> > >> to
>>> > >> > >> > the bad datanode which should not happen because of the stale
>>> > node
>>> > >> > >> timeout)
>>> > >> > >> > Unfortunately it hits the 45 retries and a connect timeout
>>> of 20
>>> > >> > seconds
>>> > >> > >> > every time. This delays recovery significantly. Now I guess
>>> > >> reducing #
>>> > >> > >> of
>>> > >> > >> > retries to 1 is one possibility.
>>> > >> > >> > But then the namenode logs are very interesting.
>>> > >> > >> >
>>> > >> > >> > d) Namenode seems to be in cyclic lease recovery loop until
>>> the
>>> > >> node
>>> > >> > is
>>> > >> > >> > marked dead. There is this one last block which exhibits
>>> this.
>>> > >> > >> >
>>> > >> > >> > 2013-04-19 00:28:09,744 INFO BlockStateChange: BLOCK* blk_-*
>>> > >> > >> > 5723958680970112840_174056*{blockUCState=UNDER_RECOVERY,
>>> > >> > >> > primaryNodeIndex=1,
>>> > >> > >> > replicas=[ReplicaUnderConstruction[10.156.194.94:50010|RBW],
>>> > >> > >> > ReplicaUnderConstruction[10.156.192.106:50010|RBW],
>>> > >> > >> > ReplicaUnderConstruction[10.156.195.38:50010|RBW]]} recovery
>>> > >> started,
>>> > >> > >> > primary=10.156.192.106:50010
>>> > >> > >> > 2013-04-19 00:28:09,744 WARN
>>> org.apache.hadoop.hdfs.StateChange:
>>> > >> DIR*
>>> > >> > >> > NameSystem.internalReleaseLease: File
>>> > >> > >> >
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> /hbase/.logs/ip-10-156-194-94.ec2.internal,60020,1366323217601-splitting/ip-10-156-194-94.ec2.internal%2C60020%2C1366323217601.1366331156141
>>> > >> > >> > has not been closed. Lease recovery is in progress.
>>> RecoveryId =
>>> > >> > 174413
>>> > >> > >> for
>>> > >> > >> > block
>>> > blk_-5723958680970112840_174056{blockUCState=UNDER_RECOVERY,
>>> > >> > >> > primaryNodeIndex=1,
>>> > >> > >> > replicas=[ReplicaUnderConstruction[10.156.194.94:50010|RBW],
>>> > >> > >> > ReplicaUnderConstruction[10.156.192.106:50010|RBW],
>>> > >> > >> > ReplicaUnderConstruction[10.156.195.38:50010|RBW]]}
>>> > >> > >> >
>>> > >> > >> > I see this over and over again in the logs until the
>>> datanode is
>>> > >> > marked
>>> > >> > >> > dead. It seems to be cycling through the replicas for this
>>> WAL
>>> > >> block
>>> > >> > and
>>> > >> > >> > trying to add it to the recovery list. I looked at the code
>>> and
>>> > it
>>> > >> > says:
>>> > >> > >> >
>>> > >> > >> > // Cannot close file right now, since the last block
>>> > requires
>>> > >> > >> > recovery.
>>> > >> > >> > // This may potentially cause infinite loop in lease
>>> > recovery
>>> > >> > >> > // if there are no valid replicas on data-nodes.
>>> > >> > >> > NameNode.stateChangeLog.warn(
>>> > >> > >> > "DIR* NameSystem.internalReleaseLease: " +
>>> > >> > >> > "File " + src + " has not been closed." +
>>> > >> > >> > " Lease recovery is in progress. " +
>>> > >> > >> > "RecoveryId = " + blockRecoveryId + " for
>>> block
>>> > " +
>>> > >> > >> > lastBlock);
>>> > >> > >> > break;
>>> > >> > >> >
>>> > >> > >> > Eventually for this block, we get
>>> > >> > >> >
>>> > >> > >> > 2013-04-19 00:41:20,736 INFO
>>> > >> > >> > org.apache.hadoop.hdfs.server.namenode.FSNamesystem:
>>> > >> > >> >
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> commitBlockSynchronization(lastblock=BP-696828882-10.168.7.226-1364886167971:blk_-
>>> > >> > >> > *5723958680970112840_174056*, newgenerationstamp=174413,
>>> > >> > >> > newlength=119148648, newtargets=[10.156.192.106:50010,
>>> > >> > >> 10.156.195.38:50010
>>> > >> > >> > ],
>>> > >> > >> > closeFile=true, deleteBlock=false)
>>> > >> > >> > 2013-04-19 00:41:20,736 ERROR
>>> > >> > >> > org.apache.hadoop.security.UserGroupInformation:
>>> > >> > >> PriviledgedActionException
>>> > >> > >> > as:hdfs (auth:SIMPLE) cause:java.io.IOException: Block
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> (=BP-696828882-10.168.7.226-1364886167971:blk_-5723958680970112840_174056)
>>> > >> > >> > not found
>>> > >> > >> > 2013-04-19 00:41:20,736 INFO org.apache.hadoop.ipc.Server:
>>> IPC
>>> > >> Server
>>> > >> > >> > handler 35 on 8020, call
>>> > >> > >> >
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol.commitBlockSynchronization
>>> > >> > >> > from 10.156.192.106:53271: error: java.io.IOException: Block
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> (=BP-696828882-10.168.7.226-1364886167971:blk_-5723958680970112840_174056)
>>> > >> > >> > not found
>>> > >> > >> >
>>> > >> > >> > On the datanode side, i see a call for recover blocks - I see
>>> > that
>>> > >> a
>>> > >> > >> write
>>> > >> > >> > pipeline is there, which gets terminated with some socket
>>> > >> timeouts...
>>> > >> > >> >
>>> > >> > >> > 00:28:11,471 INFO
>>> > org.apache.hadoop.hdfs.server.datanode.DataNode:
>>> > >> > >> NameNode
>>> > >> > >> > at
>>> > ec2-107-20-237-30.compute-1.amazonaws.com/10.168.7.226:8020calls
>>> > >> > >> >
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> recoverBlock(BP-696828882-10.168.7.226-1364886167971:blk_-5723958680970112840_174056,
>>> > >> > >> > targets=[10.156.194.94:50010, 10.156.192.106:50010,
>>> > >> > 10.156.195.38:50010
>>> > >> > >> ],
>>> > >> > >> > newGenerationStamp=174413)
>>> > >> > >> >
>>> > >> > >> > Not sure but this looks like a case where data could be lost
>>> ?
>>> > >> > >> >
>>> > >> > >> > Varun
>>> > >> > >> >
>>> > >> > >> >
>>> > >> > >> > On Fri, Apr 19, 2013 at 12:38 AM, Nicolas Liochon <
>>> > >> nkey...@gmail.com>
>>> > >> > >> > wrote:
>>> > >> > >> >
>>> > >> > >> > > Hey Varun,
>>> > >> > >> > >
>>> > >> > >> > > Could you please share the logs and the configuration
>>> (hdfs /
>>> > >> hbase
>>> > >> > >> > > settings + cluster description). What's the failure
>>> scenario?
>>> > >> > >> > > From an HDFS pov, HDFS 3703 does not change the dead node
>>> > status.
>>> > >> > But
>>> > >> > >> > these
>>> > >> > >> > > node will be given the lowest priority when reading.
>>> > >> > >> > >
>>> > >> > >> > >
>>> > >> > >> > > Cheers,
>>> > >> > >> > >
>>> > >> > >> > > Nicolas
>>> > >> > >> > >
>>> > >> > >> > >
>>> > >> > >> > > On Fri, Apr 19, 2013 at 3:01 AM, Varun Sharma <
>>> > >> va...@pinterest.com>
>>> > >> > >> > wrote:
>>> > >> > >> > >
>>> > >> > >> > > > Hi,
>>> > >> > >> > > >
>>> > >> > >> > > > We are facing problems with really slow HBase region
>>> server
>>> > >> > >> recoveries
>>> > >> > >> > ~
>>> > >> > >> > > 20
>>> > >> > >> > > > minuted. Version is hbase 0.94.3 compiled with
>>> > >> hadoop.profile=2.0.
>>> > >> > >> > > >
>>> > >> > >> > > > Hadoop version is CDH 4.2 with HDFS 3703 and HDFS 3912
>>> > patched
>>> > >> and
>>> > >> > >> > stale
>>> > >> > >> > > > node timeouts configured correctly. Time for dead node
>>> > >> detection
>>> > >> > is
>>> > >> > >> > still
>>> > >> > >> > > > 10 minutes.
>>> > >> > >> > > >
>>> > >> > >> > > > We see that our region server is trying to read an HLog
>>> is
>>> > >> stuck
>>> > >> > >> there
>>> > >> > >> > > for
>>> > >> > >> > > > a long time. Logs here:
>>> > >> > >> > > >
>>> > >> > >> > > > 2013-04-12 21:14:30,248 WARN
>>> > org.apache.hadoop.hdfs.DFSClient:
>>> > >> > >> Failed
>>> > >> > >> > to
>>> > >> > >> > > > connect to /10.156.194.251:50010 for file
>>> > >> > >> > > >
>>> > >> > >> > > >
>>> > >> > >> > >
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> /hbase/feeds/fbe25f94ed4fa37fb0781e4a8efae142/home/1d102c5238874a5d82adbcc09bf06599
>>> > >> > >> > > > for block
>>> > >> > >> > > >
>>> > >> > >> > > >
>>> > >> > >> > >
>>> > >> > >> >
>>> > >> > >>
>>> > >> >
>>> > >>
>>> >
>>> BP-696828882-10.168.7.226-1364886167971:blk_-3289968688911401881_9428:java.net.SocketTimeoutException:
>>> > >> > >> > > > 15000 millis timeout while waiting for channel to be
>>> ready
>>> > for
>>> > >> > read.
>>> > >> > >> > ch :
>>> > >> > >> > > > java.nio.channels.SocketChannel[connected local=/
>>> > >> > >> 10.156.192.173:52818
>>> > >> > >> > > > remote=/
>>> > >> > >> > > > 10.156.194.251:50010]
>>> > >> > >> > > >
>>> > >> > >> > > > I would think that HDFS 3703 would make the server fail
>>> fast
>>> > >> and
>>> > >> > go
>>> > >> > >> to
>>> > >> > >> > > the
>>> > >> > >> > > > third datanode. Currently, the recovery seems way too
>>> slow
>>> > for
>>> > >> > >> > production
>>> > >> > >> > > > usage...
>>> > >> > >> > > >
>>> > >> > >> > > > Varun
>>> > >> > >> > > >
>>> > >> > >> > >
>>> > >> > >> >
>>> > >> > >>
>>> > >> > >
>>> > >> > >
>>> > >> >
>>> > >>
>>> > >
>>> > >
>>> >
>>>
>>
>>
>
