A number of factors are contributing to the widespread adoption of the all flash storage array, including greater storage density, which allows companies to store data from data warehouse and other analytic systems at a per gigabyte cost that is almost the same as a storage array with HDDs.
Indeed, according to Paul Silver, vice president, EMEA for Tegile, a Western Digital brand, “the high levels in density of modern flash devices allow these arrays to operate with nearly the same levels of storage density as an HDD-based array.”
As he sees the storage landscape, all flash storage arrays offer a number of benefits to the modern data centre, with perhaps the first and most important being the high IOPS at low latency that only flash storage can offer.
Moreover, says Silver, “by significantly reducing data volumes, these technologies help companies save money by lowering their storage expenditures and protecting existing investments. In addition, decreasing the number of storage arrays required in the data centre also leads to lower energy and cooling costs.”
So what is the impact on storage costs?
According to Silver, storage cost is typically measured in two metrics—cost per IOPS and cost per GB/TB. “In the case of cost per IOPS,” Silver says, “there is almost no comparison between flash and HDD. A basic example of this is a PCIe SSD which costs $2,500 and delivers 400,000 IOPS, or less than a penny per IOPS. Even a high performing HDD like a 15k SAS disk, would cost $150 and deliver only about 180 IOPS. This is almost a dollar per IOPS, or over a hundred times more than flash.
On the other hand, he says, when looking at costs and density, the density of HDDs has the cost-per-GB equation in their favour. The PCIe SSD in the previous example costs $2,500 and has a capacity of 1TB, giving it a cost of $2.44/GB. The HDD costs $150 and has a capacity of 600GB giving it a cost-per-GB of $0.25.
“What brings these two metrics together in favour of flash is that as workloads need more IOPS (due to the demands of real-time analytics and processing applications), the cost of adding IOPS to a traditional array is very expensive based on the sheer number of HDDs required to service those IOPS. The added functionality of compression, encryption, and snapshots help tilt this equation in favour of the all flash arrays.”