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From Harsh J <ha...@cloudera.com>
Subject Re: Help. Strange thing. It's block me 1 week....
Date Fri, 18 Jan 2013 07:04:17 GMT
What are your number of map and reduce slots configured to, per node? Also
noticed you seem to be requesting 4 GB memory from Reducers when your
slaves' maximum RAM itself nears that - the result may not be so good here
and can certainly cause slowdowns (due to swapping/etc.).


On Fri, Jan 18, 2013 at 8:47 AM, yaotian <yaotian@gmail.com> wrote:

> Hi,
>
> *=>My machine environment:*
> 1 master 1 CPU core, 2G Mhz, 1G Memory
> 2 Slaves(datanode): 1 CPU core, 2G Mhz, 4G memory
> hadoop: hadoop-0.20.205.0
>
> *=> My data:*
> User GPS trace analysis. Each user has many gp location information. We
> want to analyze them.
>
> *=>My question:*
> 1. We have 2 datanode. But hadoop only used only 1 server? Is that not
> effective?
>
> 2. When i run the 200M size data. It is successful. But if i run 30G data,
> it always to report "Task attempt_201301171429_0013_r_000000_0 failed to
> report status for 600 seconds. Killing!"
>
> *=>My map-reduce config:*
> <configuration>
>
>      <property>
>          <name>mapred.job.tracker</name>
>          <value>master:9001</value>
>      </property>
>
>
> <property>
>   <name>mapred.reduce.parallel.copies</name>
>   <value>50</value>
> </property>
>
> <property>
>   <name>mapred.compress.map.output</name>
>   <value>true</value>
> </property>
>
>
> <property>
>   <name>mapred.job.shuffle.merge.percent</name>
>   <value>0.75</value>
> </property>
>
>
> <property>
>   <name>mapred.job.tracker.http.address</name>
>   <value>0.0.0.0:9003</value>
> </property>
>
>
> <property>
>   <name>mapreduce.reduce.memory.mb</name>
>   <value>4000</value>
> </property>
>
> <property>
>   <name>mapred.child.java.opts</name>
>   <value>-Xmx2000m</value>
> </property>
>
> <property>
>   <name>mapreduce.reduce.java.opts</name>
>   <value>-Xmx2000m</value>
> </property>
>
>
> <property>
>   <name>mapred.reduce.tasks</name>
>   <value>AutoReduce</value>
> </property>
>
> <property>
>   <name>io.sort.factor</name>
>   <value>12</value>
> </property>
>
> <property>
>   <name>io.sort.mb</name>
>   <value>300</value>
> </property>
>
>
> <property>
>   <name>io.file.buffer.size</name>
>   <value>65536</value>
> </property>
>
> <property>
>   <name>dfs.datanode.handler.count</name>
>   <value>8</value>
> </property>
>  </configuration>
>
>
>
>
>
>
>


-- 
Harsh J

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