Anything that possibly gets started is another MR job working on other
dataset in the same time as this test was running. So some node might  be
under heavy loads.
I am wondering whether that would cause the connection timeout.

thanks
zhenyu



On Thu, Oct 29, 2009 at 5:32 PM, stack <[email protected]> wrote:

> On Thu, Oct 29, 2009 at 2:23 PM, Zhenyu Zhong <[email protected]
> >wrote:
>
> > I have 19 quorum members now.
> >
> > Thats too many.  Have 3 or maybe 5.  See zk site for rationale.
>
>
>
> > When I did test on loading data to two columnfamilies of one table in
> HBase
> > using two seperate MR jobs, I lost my regionserver and the test failed.
> >
> > Does HBase allow such table update operation?
> >
> > The errors I got while I lost my regionserver is:
> > 2009-10-29 21:09:34,705 INFO org.apache.hadoop.hbase.regionserver.HLog:
> > Roll
> > /hbase/.logs/YYYY,60021,1256849619429/hlog.d
> > at.1256849620029, entries=271911, calcsize=63754142, filesize=33975611.
> New
> > hlog /hbase/.logs/YYYY,60021,1256849619429/hl
> > og.dat.1256850574705
> > 2009-10-29 21:09:50,322 WARN
> > org.apache.hadoop.hbase.regionserver.HRegionServer: Attempt=1
> > org.apache.hadoop.hbase.Leases$LeaseStillHeldException
> >
>
>
> You have read the 'Getting Started' and made the necessary changes to
> filedescriptors and xceiver count?
>
> You will see above message after a regionserver has restarted and tries to
> go back to the master (what hbase is this? I think you said it 0.20.x).
>
>
>
>
> > java.io.IOException: TIMED OUT
> >        at
> > org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:906)
> > 2009-10-29 21:09:50,873 INFO
> > org.apache.hadoop.hbase.regionserver.HRegionServer: Got ZooKeeper event,
> > state: Disconnected, type: None, path:
> > null
> >
>
> This is timeout against zk.  You've lost your session.  The RS will go
> down.  The connection to zk is basic to hbase.  Something is up.  In the
> past others have reported things like incorrect bios settings on disks that
> have made the disks run slow or just something up with the networking.  Can
> you check all is healthy?  You seem to be having too many issues for such a
> small loading with such a large cluster.
>
> St.Ack
>
>
>
> >
> >
> >
> >
> > On Thu, Oct 29, 2009 at 2:51 PM, stack <[email protected]> wrote:
> >
> > > On Thu, Oct 29, 2009 at 11:46 AM, Zhenyu Zhong <
> [email protected]
> > > >wrote:
> > >
> > > > FYI
> > > > It looks like increasing the number of Zookeeper Quorums can solve
> the
> > > > following error message : org.apache.hadoop.hbase.
> > > > client.NoServerForRegionException: Timed out trying to locate root
> > region
> > > > at
> > > > org.apache.hadoop.hbase.
> > > >
> > > > You mean quorum members?  How many do you have now?
> > >
> > >
> > >
> > > > Now I am running Zookeeper quorum on each node I have.
> > > > However, I am still having issues about losing regionserver.
> > > >
> > > > Whats in the logs?
> > >
> > >
> > >
> > >
> > > > Is there a way to browse the Znode in zookeeper?
> > > >
> > > >
> > > Type 'zk' in the hbase shell.
> > >
> > > You can get to the zk shell from hbase shell.  You so things like:
> > >
> > > > zk "ls /"
> > >
> > > (Yes, quotes needed).
> > >
> > > St.Ack
> > >
> > >
> > >
> > > > thanks
> > > > zhenyu
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > On Wed, Oct 28, 2009 at 3:40 PM, Zhenyu Zhong <
> [email protected]
> > > > >wrote:
> > > >
> > > > > JG,
> > > > >
> > > > >
> > > > > Thanks a lot for the tips.
> > > > > I set the HEAP to 4GB and GC options as -XX:ParallelGCThreads=8
> > > > >  -XX:+UseConcMarkSweepGC.
> > > > >
> > > > > I checked the logs in my Master an RS and found the following
> errors.
> > > > > Basically, master got exception error while scanning ROOT, then the
> > > ROOT
> > > > > region was offline and unset.  Thus the regionserver can't get
> > > > > NotservingRegion errors.
> > > > >
> > > > > In the master:
> > > > > 2009-10-28 19:00:30,591 INFO
> > > org.apache.hadoop.hbase.master.BaseScanner:
> > > > > RegionManager.rootScanner scanning meta region {server: x.x.x.
> > > > > x:60021, regionname: -ROOT-,,0, startKey: <>}
> > > > > 2009-10-28 19:00:30,591 WARN
> > > org.apache.hadoop.hbase.master.BaseScanner:
> > > > > Scan ROOT region
> > > > > java.io.IOException: Call to /x.x.x.x:60021 failed on local
> > exception:
> > > > > java.io.EOFException
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.ipc.HBaseClient.wrapException(HBaseClient.java:757)
> > > > >         at
> > > > > org.apache.hadoop.hbase.ipc.HBaseClient.call(HBaseClient.java:727)
> > > > >         at
> > > > >
> > org.apache.hadoop.hbase.ipc.HBaseRPC$Invoker.invoke(HBaseRPC.java:328)
> > > > >         at $Proxy1.openScanner(Unknown Source)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.master.BaseScanner.scanRegion(BaseScanner.java:160)
> > > > >         at
> > > > >
> > >
> org.apache.hadoop.hbase.master.RootScanner.scanRoot(RootScanner.java:54)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.master.RootScanner.maintenanceScan(RootScanner.java:79)
> > > > >         at
> > > > >
> > org.apache.hadoop.hbase.master.BaseScanner.chore(BaseScanner.java:136)
> > > > >         at org.apache.hadoop.hbase.Chore.run(Chore.java:68)
> > > > > Caused by: java.io.EOFException
> > > > >         at
> java.io.DataInputStream.readInt(DataInputStream.java:375)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.receiveResponse(HBaseClient.java:504)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.run(HBaseClient.java:448)
> > > > > 2009-10-28 19:00:30,591 INFO
> > > org.apache.hadoop.hbase.master.BaseScanner:
> > > > > RegionManager.metaScanner scanning meta region {server: x.x.x.
> > > > > x:60021, regionname: .META.,,1, startKey: <>}
> > > > > 2009-10-28 19:00:30,591 WARN
> > > org.apache.hadoop.hbase.master.BaseScanner:
> > > > > Scan one META region: {server: x.x.x.x:60021, regionname: .M
> > > > > ETA.,,1, startKey: <>}
> > > > > java.net.ConnectException: Connection refused
> > > > >         at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
> > > > >         at
> > > > >
> > sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:574)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
> > > > >         at
> org.apache.hadoop.net.NetUtils.connect(NetUtils.java:404)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.setupIOstreams(HBaseClient.java:308)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.ipc.HBaseClient.getConnection(HBaseClient.java:831)
> > > > >         at
> > > > > org.apache.hadoop.hbase.ipc.HBaseClient.call(HBaseClient.java:712)
> > > > >         at
> > > > >
> > org.apache.hadoop.hbase.ipc.HBaseRPC$Invoker.invoke(HBaseRPC.java:328)
> > > > >         at $Proxy1.openScanner(Unknown Source)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.master.BaseScanner.scanRegion(BaseScanner.java:160)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.master.MetaScanner.scanOneMetaRegion(MetaScanner.java:73)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.master.MetaScanner.maintenanceScan(MetaScanner.java:129)
> > > > >         at
> > > > >
> > org.apache.hadoop.hbase.master.BaseScanner.chore(BaseScanner.java:136)
> > > > >         at org.apache.hadoop.hbase.Chore.run(Chore.java:68)
> > > > > 2009-10-28 19:00:30,591 INFO
> > > org.apache.hadoop.hbase.master.BaseScanner:
> > > > > All 1 .META. region(s) scanned
> > > > > 2009-10-28 19:00:31,395 INFO
> > > > org.apache.hadoop.hbase.master.ServerManager:
> > > > > Removing server's info YYYY,60021,125675547057
> > > > > 0
> > > > > 2009-10-28 19:00:31,395 INFO
> > > > org.apache.hadoop.hbase.master.RegionManager:
> > > > > Offlined ROOT server: x.x.x.x:60021
> > > > >
> > > > > 2009-10-28 19:00:31,395 INFO
> > > > org.apache.hadoop.hbase.master.RegionManager:
> > > > > -ROOT- region unset (but not set to be reassigned)
> > > > > 2009-10-28 19:00:31,395 INFO
> > > > org.apache.hadoop.hbase.master.RegionManager:
> > > > > ROOT inserted into regionsInTransition
> > > > > 2009-10-28 19:00:31,395 INFO
> > > > org.apache.hadoop.hbase.master.RegionManager:
> > > > > Offlining META region: {server: x.x.x.x:60021, regionname:
> .META.,,1,
> > > > > startKey: <>}
> > > > > 2009-10-28 19:00:31,395 INFO
> > > > org.apache.hadoop.hbase.master.RegionManager:
> > > > > META region removed from onlineMetaRegions
> > > > >
> > > > >
> > > > >
> > > > > On the regionserver:
> > > > > 2009-10-28 18:51:14,578 INFO
> > > > > org.apache.hadoop.hbase.regionserver.HRegionServer:
> MSG_REGION_OPEN:
> > > > > test,,1256755871065
> > > > > 2009-10-28 18:51:14,578 INFO
> > > > > org.apache.hadoop.hbase.regionserver.HRegionServer: Worker:
> > > > MSG_REGION_OPEN:
> > > > > test,,1256755871065
> > > > > 2009-10-28 18:51:14,578 INFO
> > > > org.apache.hadoop.hbase.regionserver.HRegion:
> > > > > region test,,1256755871065/796855017 available; sequence id is
> > 10013291
> > > > > 2009-10-28 18:51:14,578 INFO
> > > > org.apache.hadoop.hbase.regionserver.HRegion:
> > > > > Starting compaction on region test,,1256755871065
> > > > > 2009-10-28 18:51:18,388 DEBUG org.apache.zookeeper.ClientCnxn: Got
> > ping
> > > > > response for sessionid:0x249c76021d0001 after 0ms
> > > > > 2009-10-28 18:51:19,341 ERROR
> > > > > org.apache.hadoop.hbase.regionserver.HRegionServer:
> > > > > org.apache.hadoop.hbase.NotServingRegionException:
> > test,,1256754924503
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.HRegionServer.getRegion(HRegionServer.java:2307)
> > > > >         at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.HRegionServer.get(HRegionServer.java:1784)
> > > > >         at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown
> > Source)
> > > > >         at
> > > > >
> > > >
> > >
> >
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> > > > >         at java.lang.reflect.Method.invoke(Method.java:597)
> > > > >         at
> > > > > org.apache.hadoop.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:648)
> > > > >         at
> > > > >
> > >
> org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:915)
> > > > > 2009-10-28 18:51:19,341 INFO org.apache.hadoop.ipc.HBaseServer: IPC
> > > > Server
> > > > > handler 0 on 60021, call get([...@21fefd80, row=1053508149,
> > > maxVersions=1,
> > > > > timeRange=[0,9223372036854775807),
> > families={(family=email_ip_activity,
> > > > > columns=ALL}) from x.x.x.x:54669: error:
> > > > > org.apache.hadoop.hbase.NotServingRegionException:
> > test,,1256754924503
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On Wed, Oct 28, 2009 at 2:56 PM, Jonathan Gray <[email protected]>
> > > > wrote:
> > > > >
> > > > >> These client error messages are not particular descriptive as to
> the
> > > > root
> > > > >> cause (they are fatal errors, or close to it).
> > > > >>
> > > > >> What is going on in your regionservers when these errors happen?
> > >  Check
> > > > >> the master and RS logs.
> > > > >>
> > > > >> Also, you definitely do not want 19 zookeeper nodes.  Reduce that
> to
> > 3
> > > > or
> > > > >> 5 max.
> > > > >>
> > > > >> What is the hardware you are using for these nodes, and what
> > settings
> > > do
> > > > >> you have for heap/GC?
> > > > >>
> > > > >> JG
> > > > >>
> > > > >>
> > > > >> Zhenyu Zhong wrote:
> > > > >>
> > > > >>> Stack,
> > > > >>>
> > > > >>> Thank you very much for your comments.
> > > > >>> I am running a cluster with 20 nodes. I set 19 as both
> regionserver
> > > and
> > > > >>> zookeeper quorums.
> > > > >>> The versions I am using are  Hadoop0.20.1 and HBase0.20.1.
> > > > >>> I started with an empty table and try to load 200 million records
> > > into
> > > > >>> that
> > > > >>> empty table.
> > > > >>> There is a key in each record. Logically, in my MR program,
> during
> > > the
> > > > >>> setup, I opened an HTable, in my mapper, I fetch the record from
> > > HTable
> > > > >>> via
> > > > >>> key in the record, then make some changes to the columns and
> update
> > > > that
> > > > >>> row
> > > > >>> back to HTable through TableOutputFormat by passing a put. There
> is
> > > no
> > > > >>> reduce tasks involved here.  (Though it is unnecessary to fetch
> row
> > > > from
> > > > >>> an
> > > > >>> empty table, I just intended to do that)
> > > > >>>
> > > > >>> Additionally, when I reduced the number of regionservers and
> number
> > > of
> > > > >>> zookeeper quorums.
> > > > >>> I had different errors:
> > > > >>> org.apache.hadoop.hbase.client.NoServerForRegionException: Timed
> > out
> > > > >>> trying
> > > > >>> to locate root region at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.locateRootRegion(HConnectionManager.java:929)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.locateRegion(HConnectionManager.java:580)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.relocateRegion(HConnectionManager.java:562)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.locateRegionInMeta(HConnectionManager.java:693)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.locateRegion(HConnectionManager.java:589)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.relocateRegion(HConnectionManager.java:562)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.locateRegionInMeta(HConnectionManager.java:693)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.locateRegion(HConnectionManager.java:593)
> > > > >>> at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.locateRegion(HConnectionManager.java:556)
> > > > >>> at org.apache.hadoop.hbase.client.HTable.(HTable.java:127) at
> > > > >>> org.apache.hadoop.hbase.client.HTable.(HTable.java:105) at
> > > > >>>
> > > > >>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.mapreduce.TableOutputFormat.getRecordWriter(TableOutputFormat.java:116)
> > > > >>> at
> org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:573)
> > at
> > > > >>> org.apache.hadoop.mapred.MapTask.run(MapTask.java:305) at
> > > > >>> org.apache.hadoop.mapred.Child.main(Child.java:170)
> > > > >>>
> > > > >>> Many thanks in advance.
> > > > >>> zhenyu
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>> On Wed, Oct 28, 2009 at 12:39 PM, stack <[email protected]>
> wrote:
> > > > >>>
> > > > >>>  Whats your cluster topology?  How many nodes involved?  When you
> > see
> > > > the
> > > > >>>> below message, how many regions in your table?  How are you
> > loading
> > > > your
> > > > >>>> table?
> > > > >>>> Thanks,
> > > > >>>> St.Ack
> > > > >>>>
> > > > >>>> On Wed, Oct 28, 2009 at 7:45 AM, Zhenyu Zhong <
> > > > [email protected]
> > > > >>>>
> > > > >>>>> wrote:
> > > > >>>>> Nitay,
> > > > >>>>>
> > > > >>>>> I am very appreciated.
> > > > >>>>>
> > > > >>>>> As Ryan suggested, I increased the zookeeper session timeout to
> > > > >>>>> 40seconds
> > > > >>>>> along with the GC options -XX:ParallelGCThreads=8
> > > > >>>>>
> > > > >>>>  -XX:+UseConcMarkSweepGC
> > > > >>>>
> > > > >>>>> in place. I set the Heapsize to 4GB.  I also set the
> > > vm.swappiness=0.
> > > > >>>>>
> > > > >>>>> However it still ran into problem. Please find the following
> > > errors.
> > > > >>>>>
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Trying
> > to
> > > > >>>>> contact region server x.x.x.x:60021 for region
> > > > >>>>> YYYY,117.99.7.153,1256396118155, row '1170491458', but failed
> > after
> > > > 10
> > > > >>>>> attempts.
> > > > >>>>> Exceptions:
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>> org.apache.hadoop.hbase.client.RetriesExhaustedException:
> Failed
> > > > >>>>> setting up proxy to /x.x.x.x:60021 after attempts=1
> > > > >>>>>
> > > > >>>>>       at
> > > > >>>>>
> > > > >>>>>
> > > >
> > >
> >
> org.apache.hadoop.hbase.client.HConnectionManager$TableServers.getRegionServerWithRetries(HConnectionManager.java:1001)
> > > > >>>>
> > > > >>>>>       at
> > org.apache.hadoop.hbase.client.HTable.get(HTable.java:413)
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> The input file is about 10GB around 200million rows of data.
> > > > >>>>> This load doesn't seem too large. However this kind of errors
> > keep
> > > > >>>>>
> > > > >>>> popping
> > > > >>>>
> > > > >>>>> up.
> > > > >>>>>
> > > > >>>>> Does Regionserver need to be deployed to dedicated machines?
> > > > >>>>> Does Zookeeper need to be deployed to dedicated machines as
> well?
> > > > >>>>>
> > > > >>>>> Best,
> > > > >>>>> zhenyu
> > > > >>>>>
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> On Wed, Oct 28, 2009 at 1:37 AM, nitay <[email protected]>
> wrote:
> > > > >>>>>
> > > > >>>>>  Hi Zhenyu,
> > > > >>>>>>
> > > > >>>>>> Sorry for the delay. I started working on this a while back,
> > > before
> > > > I
> > > > >>>>>>
> > > > >>>>> left
> > > > >>>>>
> > > > >>>>>> my job for another company. Since then I haven't had much time
> > to
> > > > work
> > > > >>>>>>
> > > > >>>>> on
> > > > >>>>
> > > > >>>>> HBase unfortunately :(. I'll try to dig up what I had and see
> > what
> > > > >>>>>>
> > > > >>>>> shape
> > > > >>>>
> > > > >>>>> it's in and update you.
> > > > >>>>>>
> > > > >>>>>> Cheers,
> > > > >>>>>> -n
> > > > >>>>>>
> > > > >>>>>>
> > > > >>>>>> On Oct 27, 2009, at 3:38 PM, Ryan Rawson wrote:
> > > > >>>>>>
> > > > >>>>>>  Sorry I must have mistyped, I meant to say "40 seconds".  You
> > can
> > > > >>>>>>
> > > > >>>>>>> still see multi-second pauses at times, so you need to give
> > > > yourself
> > > > >>>>>>> a
> > > > >>>>>>> bigger buffer.
> > > > >>>>>>>
> > > > >>>>>>> The parallel threads argument should not be necessary, but
> you
> > do
> > > > >>>>>>> need
> > > > >>>>>>> the UseConcMarkSweepGC flag as well.
> > > > >>>>>>>
> > > > >>>>>>> Let us know how it goes!
> > > > >>>>>>> -ryan
> > > > >>>>>>>
> > > > >>>>>>>
> > > > >>>>>>> On Tue, Oct 27, 2009 at 3:19 PM, Zhenyu Zhong <
> > > > >>>>>>>
> > > > >>>>>> [email protected]>
> > > > >>>>
> > > > >>>>>  wrote:
> > > > >>>>>>>
> > > > >>>>>>>  Ryan,
> > > > >>>>>>>> I am very appreciated for your feedbacks.
> > > > >>>>>>>> I have set the zookeeper.session.timeout to seconds which is
> > way
> > > > >>>>>>>>
> > > > >>>>>>> higher
> > > > >>>>
> > > > >>>>>  than
> > > > >>>>>>>> 40ms.
> > > > >>>>>>>> In the same time, the -Xms is set to 4GB, which should be
> > > > >>>>>>>> sufficient.
> > > > >>>>>>>> I also tried GC options like
> > > > >>>>>>>>
> > > > >>>>>>>>  -XX:ParallelGCThreads=8
> > > > >>>>>>>> -XX:+UseConcMarkSweepGC
> > > > >>>>>>>>
> > > > >>>>>>>> I even set the vm.swappiness=0
> > > > >>>>>>>>
> > > > >>>>>>>> However, I still came across the problem that a RegionServer
> > > > >>>>>>>> shutdown
> > > > >>>>>>>> itself.
> > > > >>>>>>>>
> > > > >>>>>>>> Best,
> > > > >>>>>>>> zhong
> > > > >>>>>>>>
> > > > >>>>>>>>
> > > > >>>>>>>> On Tue, Oct 27, 2009 at 6:05 PM, Ryan Rawson <
> > > [email protected]>
> > > > >>>>>>>>
> > > > >>>>>>> wrote:
> > > > >>>>>
> > > > >>>>>>   Set the ZK timeout to something like 40ms, and give the GC
> > > enough
> > > > >>>>>>>>
> > > > >>>>>>> Xmx
> > > > >>>>
> > > > >>>>>  so you never risk entering the much dreaded
> > > concurrent-mode-failure
> > > > >>>>>>>>> whereby the entire heap must be GCed.
> > > > >>>>>>>>>
> > > > >>>>>>>>> Consider testing Java 7 and the G1 GC.
> > > > >>>>>>>>>
> > > > >>>>>>>>> We could get a JNI thread to do this, but no one has done
> so
> > > yet.
> > > > I
> > > > >>>>>>>>>
> > > > >>>>>>>> am
> > > > >>>>
> > > > >>>>>  personally hoping for G1 and in the meantime overprovision our
> > Xmx
> > > > >>>>>>>>>
> > > > >>>>>>>> to
> > > > >>>>
> > > > >>>>>  avoid the concurrent mode failures.
> > > > >>>>>>>>>
> > > > >>>>>>>>> -ryan
> > > > >>>>>>>>>
> > > > >>>>>>>>> On Tue, Oct 27, 2009 at 2:59 PM, Zhenyu Zhong <
> > > > >>>>>>>>>
> > > > >>>>>>>> [email protected]>
> > > > >>>>>
> > > > >>>>>>  wrote:
> > > > >>>>>>>>>
> > > > >>>>>>>>>  Ryan,
> > > > >>>>>>>>>>
> > > > >>>>>>>>>> Thank you very much.
> > > > >>>>>>>>>> May I ask whether there are any ways to get around this
> > > problem
> > > > to
> > > > >>>>>>>>>>
> > > > >>>>>>>>> make
> > > > >>>>>
> > > > >>>>>>  HBase more stable?
> > > > >>>>>>>>>>
> > > > >>>>>>>>>> best,
> > > > >>>>>>>>>> zhong
> > > > >>>>>>>>>>
> > > > >>>>>>>>>>
> > > > >>>>>>>>>>
> > > > >>>>>>>>>> On Tue, Oct 27, 2009 at 4:06 PM, Ryan Rawson <
> > > > [email protected]>
> > > > >>>>>>>>>> wrote:
> > > > >>>>>>>>>>
> > > > >>>>>>>>>>  There isnt any working code yet. Just an idea, and a
> > > prototype.
> > > > >>>>>>>>>>
> > > > >>>>>>>>>>> There is some sense that if we can get the G1 GC that we
> > > could
> > > > >>>>>>>>>>> get
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>> rid
> > > > >>>>>
> > > > >>>>>>  of all long pauses, and avoid the need for this.
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> -ryan
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> On Mon, Oct 26, 2009 at 2:30 PM, Zhenyu Zhong <
> > > > >>>>>>>>>>> [email protected]>
> > > > >>>>>>>>>>> wrote:
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>>  Hi,
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> I am very interesting to the solution that Joey proposed
> > and
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>> would
> > > > >>>>
> > > > >>>>>   like
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>> to
> > > > >>>>>>>>>>
> > > > >>>>>>>>>>> have a try.
> > > > >>>>>>>>>>>> Does anyone have any ideas on how to deploy this
> > zk_wrapper
> > > in
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>> JNI
> > > > >>>>
> > > > >>>>>   integration?
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> I would be very appreciated.
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> thanks
> > > > >>>>>>>>>>>> zhong
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>>
> > > > >>>
> > > > >
> > > >
> > >
> >
>

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