That is good information on technical issues on using a grid.
Missing is a design question for when to choose a grid approach.

Today there are two trends:
- virtualization has become a goal on his own.
There are projects being proud just on the number of OS boxes being delivered.
The real business profits to achieve are some things of an other world.
- hardware costs are dropping size is decreasing capacity is increasing. The Speed per processor does not grow but number of (logical/virtual) cpu's and internal memory capacity is still growing (moore's law)

The ethical question:
As a relative cheap box (hardware) often easily can run all needed heavy load for analytics, why should you split that up in many virtual ones and than adding the grid complexity to get those resources back again. Why?
Does it not make more sense to use a grid when the hardware building blocks is not powerfull enough to deliver the needed resources so you have to combine them.