"A rising tide lifts all boats."
This ancient proverb, most recently attributed to John F. Kennedy, is usually trotted out to explain the logic of one or the other school of economic thought. And while there is some debate as to whether it adequately justifies continued tax cuts or not, I think it does describe one facet of data center infrastructure: the debate between hard disk drives (HDD) and their solid-state contemporaries (SSDs).
To listen to the talk of a year ago, it would seem that HDDs were on the way out. SSDs were faster, cost less to operate and seemed on track to become both cheaper and provide as much capacity as hard disks in a relatively short time. These arguments carried a lot of sway as the IT industry dealt with the twin threats of decreasing budgets and steadily increasing data requirements.
But what a difference a year makes. With the economy turning around, the tide appears to be rising on both forms of storage. New numbers from IDC indicate that the hard disk industry is about to make a roaring comeback, with shipments jumping from 40.5 million units in 2009 to more than 52 million units in 2014. That would represent some 300,000 PB of storage from a technology that many were writing off as yesterday's news. At best, the company says, SDDs will likely produce a shift away from high-performance HDDs to lower-cost, high-capacity models for bulk storage applications.
Part of this is due to the fact that, despite the dire warnings, HDD manufacturers continue to churn out new HDD designs. Western Digital, for example, recently unveiled the new 600 GB version of the VeliciRaptor, essentially doubling the capacity of SATA environments on everything from blade and rack servers to top-end PCs and Macs.
There's also the fact that, while SSDs do exhibit some impressive performance gains over HDDs, they don't win on every benchmark. As CHIP's Thomas Littschwager points out, while there's no comparing the speed factor, HDDs tend to do better in price/performance ratings and stability. Even when it comes to energy consumption, the latest HDDs stack up quite well, especially when coupled with the latest power management technologies.
At the moment, then, I would say HDDs are in a pretty good position against SSDs, but that doesn't mean things won't change down the road. More than other areas of IT technology, storage formats tend to have relatively limited life spans. As Wired's Mat Blum points out in his recently eulogy to the floppy disk, capacity limitations and advanced networking finally brought the curtain down on what for years was a PC mainstay. And that was after the 3.5-inch hard plastic devices had already pushed aside the truly floppy 5.25's or even the (geez, I'm old) 8-inch disks.
If there is one conclusion I can draw from all this, it is that storage provisioning is no longer a simple process of deploy, fill to capacity and then deploy some more. With numerous types of storage offering various levels of performance, finding the right solution for individual applications becomes a much trickier proposition -- one that will require sophisticated new automation technology as application architectures become more complex.