about the overhead

Hi all, Does hadoop provide a way to let the users know the time for computation(map/reduce functions) and the time for different types of overhead (such as the startup, sorting, i/o disk, etc.) respectively? Thanks~~ Best regards, -- --- Wei

Two questions about hadoop

Hi all, I am a new user with hadoop and have some questions about it. 1)about setting the number of maps/reduces: With running hadoop on a 8-node cluster, I set mapred.map.tasks to 64 and mapred.tasktracker.map.tasks.maximum to 8, but by examining the counter "launched map tasks" from the output