Hi,
I have the same problem, can this be the reason for slow fetching ?
Thanks,
Tomislav
On Tue, 2007-11-20 at 12:57 +0100, Andrzej Bialecki wrote:
> 施兴 wrote:
> > HI
> >
> > 2007-11-20 11:07:28,712 WARN dfs.DataNode - Failed to transfer
> > blk_-3387595792800455675 to 192.168.140.244:50010 got
> > java.net.SocketException: Connection reset
> > at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:96)
> > at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
> > at
> > java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
> > at java.io.BufferedOutputStream.write(BufferedOutputStream.java:109)
> > at java.io.DataOutputStream.write(DataOutputStream.java:90)
> > at
> > org.apache.hadoop.dfs.DataNode$BlockSender.sendChunk(DataNode.java:1175)
> > at
> > org.apache.hadoop.dfs.DataNode$BlockSender.sendBlock(DataNode.java:1208)
> > at org.apache.hadoop.dfs.DataNode$DataTransfer.run(DataNode.java:1460)
> > at java.lang.Thread.run(Thread.java:619)
> >
> > Although it is a WARN, but I wanna understand why? Is it the network
> > problem?
>
> This could indicate that the target datanode is running out of resources
> - either file handles, or CPU; you should check ulimit settings on the
> user id that runs the datanode process.
>
> This issue could be intermittent, in which case the DFS will recover
> from it (hence the WARN and not FATAL).
>
> I've also seen similar issues caused by a poor quality ethernet switch
> that dropped packets, or bad cabling.
>
