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Re: 0 tasktrackers in jobtracker but all datanodes present
Gaurav
       NN memory might have hit its upper bound. As a bench mark, for every
1 million files/blocks/directories 1GB of memory is required on the NN. The
number of files in your cluster might have grown beyond this treshold. So
the options left for you would be
- If there are large number of small files, use HAR or Sequence File for
grouping the same
- Increase the NN heap

Regards
Bejoy KS

On Mon, Apr 2, 2012 at 12:08 PM, madhu phatak <[EMAIL PROTECTED]> wrote:

> Hi,
> 1. Stop the job tracker and task trackers.  - bin/stop-mapred.sh
>
>  2. Disable namenode safemode - bin/hadoop dfsadmin -safemode leave
>
> 3. Start the job tracker and tasktrackers again - bin/start-mapred.sh
>
> On Fri, Jan 13, 2012 at 5:20 AM, Ravi Prakash <[EMAIL PROTECTED]>
> wrote:
>
> > Courtesy Kihwal and Bobby
> >
> > Have you tried increasing the max heap size with -Xmx? and make sure that
> > you have swap enabled.
> >
> > On Wed, Jan 11, 2012 at 6:59 PM, Gaurav Bagga <[EMAIL PROTECTED]>
> wrote:
> >
> > > Hi
> > >
> > > hadoop-0.19
> > > I have a working hadoop cluster which has been running perfectly for
> > > months.
> > > But today after restarting the cluster, at jobtracker UI its showing
> > state
> > > INITIALIZING for a long time and is staying on the same state.
> > > The nodes in jobtracker are zero whereas all the nodes are present on
> the
> > > dfs.
> > > It says Safe mode is on.
> > > grep'ed on slaves and I see the tasktrackers running.
> > >
> > > In namenode logs i get the following error
> > >
> > >
> > > 2012-01-11 16:50:57,195 WARN  ipc.Server - Out of Memory in server
> select
> > > java.lang.OutOfMemoryError: Java heap space
> > >        at java.nio.HeapByteBuffer.<init>(HeapByteBuffer.java:39)
> > >        at java.nio.ByteBuffer.allocate(ByteBuffer.java:312)
> > >        at
> > > org.apache.hadoop.ipc.Server$Connection.readAndProcess(Server.java:804)
> > >        at org.apache.hadoop.ipc.Server$Listener.doRead(Server.java:400)
> > >        at org.apache.hadoop.ipc.Server$Listener.run(Server.java:309)
> > >
> > > Not sure why the cluster is not coming up
> > > -G
> > >
> >
>
>
>
> --
> https://github.com/zinnia-phatak-dev/Nectar
>