reply: how do I know the datanode slave status

You can press http://localhost(namenode):50030 in you IE or Firefox And find the cluster status koven welcome to www.taobao.com China [EMAIL PROTECTED] --- Hi, Is it possible to findout the status of the datanode

reply: When I system.out.println() in a map or reduce, where does it go?

The best method is find them in web. If hadoop-default.xml,find it property namemapred.job.tracker.http.address/name value0.0.0.0:50030/value description The job tracker http server address and port the server will listen on. If the port is 0 then the server will start on a free