Cloud service providers and data centers are designing storage infrastructures focused on lowering total cost of ownership (TCO) rather than just initial capital costs. These infrastructures use hundreds of thousands of servers storing petabytes of data. Cloud architects develop best practices for optimizing storage based on factors like efficient power usage, density, and reliability. The bottom line is that storage decisions are now based on evaluating value and TCO rather than just price. Key metrics for managing costs include cost-per-terabyte, watts-per-terabyte, terabytes-per-system weight, and terabytes-per-square foot.

1. TCO
What Internet search, social networking, data warehousing, online retail and banking companies all
know, because they are designing the most demanding cloud service infrastructures with hundreds
of thousands of servers managing petabytes of data, is the importance of crafting an end-to-end
storage approach which looks beyond one time capital expense to the crux of the real costs – the
operating expenses associated with TCO. Cloud architects are developing new best practices that
demonstrate the bottom line value of taking a systems-wide approach to storage. These cloud
datacenters are highly customized. Often based on open-source hardware and software, they deploy
drives optimized for specific applications that require efficient power usage, density and reliability.
The bottom line: Cloud datacenter decisions are now based on value rather than pricing and TCO is
how value is being measured. Best cost-per-TB, watt-per-TB, TB-per-system weight and TB-per-
square foot are the new metrics for managing better costs, performance, scalability and storage
efficiency.
Adopting the right storage strategy for public, private, and on-premise data center infrastructures can
make a vast difference in your ability to significantly lower TCO costs. The secret to successfully
impacting TCO goes well beyond the cost of the drives themselves or measuring efficiency in terms
of cost per gigabyte alone. By understanding and customizing infrastructure workloads, tuning how
drives are used by application or function, and tracking cost of equipment as well as watt/GB,
cost/GB, GB per square foot and IOPS/cost for those workloads, you can realize significant savings
in total cost of ownership.
Here are three areas you need to consider as you think about storage in your datacenter and TCO:
Reliability: Understand why the quality of your hard drives matter
The more reliable the drive, the less time and cost you spend maintaining it. Drives rated at HGST’s
industry’s leading benchmark of 2 million hours Mean Time Between Failure (MTBF) will experience
40 percent fewer failures during the five year life of the drive over those rated at 1.2 million hours.
Footprint: Increase the density of your existing footprint with higher capacity drives
The TCO savings of moving from 1, 2 or 3TB drives to high capacity 4TB drives is substantial. Using
4TB drives in the 32 slots results in 128 TB storage per server, while using 3TB drives results in only
96 TB storage per server. One less server translates into a 25 percent savings in power, and with 25
percent fewer rack components you could expect additional savings of 25 percent in cooling, 25
percent less rack space and 25 percent less weight.
Additionally, new up-and-coming helium-filled platforms are capable of supporting seven platters per
standard 3.5-inch HDD, two more platters or disks than the current air-filled five-platter drives. As a
result of the helium filling, the seven disk drives will deliver massive capacity while consuming 23

2. percent less power per drive, delivering 45 percent better power density and running four degrees
Celsius cooler -- reducing power and cooling requirements in the system rack and the data center for
greater TCO.
Power: Learn from the Cloud Masters – A PUE of 1
Power Usage Efficiency or PUE refers to the ratio of the total amount of power used by a datacenter
to the power delivered or consumed by its equipment. PUE helps you measure such factors such
cooling, power distribution and lighting. The ideal PUE ratio is 1.
Best-in-class datacenters such as Google and eBay have reported ratios as low as 1.14 and 1.35,
respectively, but a typical datacenter has a ratio of 2.5, according to the Uptime Institute. This means
that a typical datacenter uses two-and-a-half times more electricity than the amount needed to run
the actual equipment.
Key Metrics for TCO