Yes, I also found that the TaskTracker should not use so much memory. PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
32480 schubert 35 10 1411m 172m 9212 S 0 2.2 8:54.78 java The previous 1GB is the default value, I have just change the heap of TT to 384MB one hours ago. I also found DataNode also need not too much memory. PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 32399 schubert 25 0 1638m 372m 9208 S 2 4.7 32:46.28 java In fact, I define the -Xmx512m in child opt for MapReduce tasks. But I found the child task use more memory than the definition: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 10577 schubert 30 10 942m 572m 9092 S 46 7.2 51:02.21 java 10507 schubert 29 10 878m 570m 9092 S 48 7.1 50:49.52 java Schubert On Tue, May 12, 2009 at 6:53 PM, Steve Loughran <ste...@apache.org> wrote: > zsongbo wrote: > >> Hi Stefan, >> Yes, the 'nice' cannot resolve this problem. >> >> Now, in my cluster, there are 8GB of RAM. My java heap configuration is: >> >> HDFS DataNode : 1GB >> HBase-RegionServer: 1.5GB >> MR-TaskTracker: 1GB >> MR-child: 512MB (max child task is 6, 4 map task + 2 reduce task) >> >> But the memory usage is still tight. >> > > does TT need to be so big if you are running all your work in external VMs? >
