Like most other things, technology suffers from advancing age.  That leading-edge wonder of just a few years ago is today’s mainstream system.  This aging process creates great headaches for IT departments, who constantly see “the bar” being moved upward.  Just when it seems like the computing environment is under control, equipment needs to be updated.

Unless a company is well disciplined in enforcing their technical refresh cycle, the aging process can also lure some organizations into a trap.  The thinking goes something like this – “Why not put off a technology update by a year or two?  Budgets are tight, the IT staff is overworked, and things seem to be going along just fine.”  It makes sense, doesn’t it?

Well, not exactly.  If you look beyond the purchase and migration expenses, there are other major cost factors to consider.

Power Reduction:  There have been major changes in storage device energy efficiency over the past decade.  Five years ago the 300GB, 15K RPM 3.5-inch drive was leading-edge technology.  Today, that has disk been superseded by 2.5-inch disks of the same speed and capacity.  Other than its physical size, other major changes are the disk’s interface (33% faster than Fibre Channel) and its power consumption (about 70% less than a 3.5-inch drive).  For 100TB of raw storage, $3577 per year could be saved by reduced power consumption alone.

Cooling Cost Reduction:  A by-product of converting energy to power is heat, and systems used to eliminate heat consume power too.  The following chart compares the cost for cooling 100TB of 3.5-inch disks with the same capacity provided by 2.5-disks.  Using 2.5-inch disks, cooling costs could be reduced by $3548 per year, per 100TB of storage.

Floor Space Reduction:  Another significant data center cost is for floor space.  This expense can vary widely, depending on the type resources provided and level of high availability guaranteed by the Service Level Agreement.  For the purpose of cost comparison, we’ll take a fairly conservative $9600 per equipment rack per year.  We will also assume fractional amounts are available, although in the real world full rack pricing might be required.  Given the higher density provided by 2.5-inch disks, a cost savings of $9,371 would be achieved.

In the example above, simply replacing aging 300GB, 15K RPM 3.5-inch FC disk drives with the latest 300GB, 15K RPM 2.5-inch FC disk drives will yield the following operational costs (OPEX) savings:

Reduced power             $   3,577
Reduced cooling           $   3,548
Less floor space            $   9,371
.                                  ========
Total Savings              $ 16,496 per 100TB of storage 

Over a storage array’s standard 5-year service cycle, OPEX savings could result in as much as $82K dollars or more.

Addition benefits from a storage refresh might also include tiering storage (typically yielding around a 30% savings over non-tiered storage), reduced support contract costs, and less time spent managing older, more labor-intensive storage subsystems.  There is also an opportunity for capital expense (CAPEX) savings by cleverly designing cost-optimized equipment, but that’s a story for a future article.

Don’t be misled into thinking that a delay of your storage technical refresh cycle will save money.  In the end it could be a very costly decision.