how to set mapred.tasktracker.map.tasks.maximum and mapred.tasktracker.reduce.tasks.maximum

[hao.wang]

Hi ,all
    Our hadoop cluster has 22 nodes including one namenode, one jobtracker and 
20 datanodes.
    Each node has 2 * 12 cores with 32G RAM
    Dose anyone tell me how to config following parameters:
    mapred.tasktracker.map.tasks.maximum
    mapred.tasktracker.reduce.tasks.maximum

regards!
2012-01-09 



hao.wang