Yes, use the CapacityScheduler and ask for multiple slots per map or reduce task:
On Oct 30, 2012, at 8:49 AM, Marco Zühlke wrote:
> on our cluster our jobs usually satisfied with less than 2 GB of heap space.
> so we have on our 8 GB computers 3 maps maximum and on our 16 GB
> computers 4 maps maximum (we only have quad core CPUs and to have
> memory left for reducers). This works very well.
> But now we have a new kind of jobs. Each mapper requires at lest 4 GB
> of heap space.
> Is it possible to limit the number of tasks (mapper) per computer to 1 or 2 for
> these kinds of jobs ?
Arun C. Murthy