Words games are not the sole prerogative of the politician. Our marketing colleagues have a tendency to push the envelope with the latest example being some folk’s interpretation of the term Storage Utilization.
When I think of storage utilization I tend to think of the capacity available to the user to perform useful work after all system overhead has been considered. I do not consider the capacity required to protect or manage stored data as user available storage. So when data is being protected with mirroring for example, storage utilization is significantly less than when RAID 5 or RAID 6 is implemented.
Date Protection Scheme..................Storage Penalty
Mirrored...........................................50%
RAID 5.............................................17% (5+1 Raid Group)
RAID 6.............................................33% (4+2 Raid Group)
Except in the case of mirroring the bigger the RAID group the smaller the penalty which is one of the configuration compromises, now add the system OS etc, you get the point.
So when you see eye catching guarantees of Storage Utilization make sure you understand how this utilization is being defined. You may be surprised.