Am 14.09.2012 um 08:03 schrieb Jason Yang <[EMAIL PROTECTED]>:
> I have a question about how does the pseudo-distributed Hadoop cluster work:
> As many map tasks are submitted to the pseudo-distributed Hadoop cluster, does the hadoop run each mapper in sequence ? or does it run these mappers in different threads or something could be parallel?
pseudo-distributed mode is a one node cluster. You have a namenode, a jobtracker, and a single datanode and tasktracker running. You can verify with "jps" command.
The default setting is that a tasktracker can run up to two map and reduce tasks in parallel (mapred.tasktracker.map.tasks.maximum and mapred.tasktracker.reduce.tasks.maximum), so you will actually see some concurrency on your one machine.