There has been some confusion in the past regarding free space defragmentation. Some people in the industry believed that after a defragmentation job free space should be consolidated into one pool. Here at Diskeeper Corporation we have long since maintained that this doesn't make sense (see our
whitepaper on this very subject). Moving free space into one consolidated pool is a temporary condition that wastes resources and serves no purpose. Instead free space should be grouped in a few contiguous pools. I was happy to see Microsoft has recently validated our longstanding position. Checkout the section on free space fragmentation in the new Microsoft TechNet
article, Maintaining Windows 2000 Peak Performance through Defragmentation:
"Free Space Fragmentation A partially full disk contains unused space, known as free space. Ideally, this space would be available in a few contiguous portions of the disk." -Microsoft TechNet -Paul