Can a hadoop job be paused or suspended?
I'm using hadoop-0.20.2.
Looking at hadoop fs. I am able to kill or fail an individual task. Is there anyway to pause it so that the map slots are freed up for another task?
No. You can't suspend a job.
There isn't. Slots are assigned for the duration of the tasks.
You can decrease the priority in the scheduler which will allow some slots to be reclaimed as tasks complete.