How the Galaxy In-Memory Data Grid Handles Failures(blog.paralleluniverse.co)

  A Data Grid is an architecture or set of services that enable individuals 
  or groups of users the ability to access, modify and transfer extremely 
  large amounts of geographically distributed data for research 
  purposes.[1] Data grids make this possible through a host of middleware 
  applications and services that pull together data and resources from 
  multiple administrative domains and then present it to users upon request.