Hi, I have an issues with hadoop dfs, I have 3 servers (24Gb RAM on each). The servers are not overloaded, they just have hadoop installed. One have datanode and namenode, second - datanode only, third - datanode and secondarynamenode.
Hadoop datanodes have a max memory limit 8Gb. Default replication factor - 2. Limited replication bandwidth between datanodes - 5Mb. I've setupped hadoop to communicate between nodes by IP address. Everything is works - I can read/write files on each datanode, etc. But the issue is that hadoop dfs commands are executing very slow, even "hadoop dfs -ls /" takes about 3 seconds to execute, but it have only one folder /user in it. Files are also uploading to the hdfs very slow - hundreds kilobytes/second. I'm using Debian stable x86-64 distribution and hadoop running through sun-java6-jdk 6.26-0squeeze1 Please give me any suggestions what I need to adjust/check to arrange this issue. As I said before - overall hdfs configuration is correct, because everything works except performance. -- Best regards Alexey
