There is much attention being paid to primary storage optimization, compression, deduplication and archiving, but none of the techniques will work on one of the biggest consumers of primary storage: allocated but unused storage. Various studies are available that indicate as much as 75% of the capacity in a medium sized and larger data center is allocated but not written. Of the remaining 25% that is in use, 80% of that capacity and its data – about 20% of the capacity in a medium-sized and large data center -- has not been accessed in the last 90 days and is eligible for some form of data reduction technique.