OK, it is still a pyramid
Predictions of the storage array’s death struck some commenters as premature. Commenters raised a host of issues:
- Cost. Low-end storage arrays are cheaper than clusters.
- Complexity. The complexity of clustered hardware – all those cables and boxes – increases management costs
- Functionality. “Unless the cluster storage also provides the same reliability, scalability, and supportability as the larger monolithic arrays. . . ” it won’t supplant traditional arrays.
- Cost pt. II: Lower-cost modular arrays, combined with a software layer that knits them into a seamless whole, could provide a full-service storage infrastructure complementing today’s virtual servers.
History repeats itself
The issues are similar to the mainframe vs everybody arguments of the last 40 years. Within living memory mainframes from IBM and the 7 dwarfs – Burroughs, Sperry Rand, NCR, RCA, Honeywell, CDC and GE – went through the same process monolithic storage arrays will.
Mainframes faced the same negatives: costly; complex management; inflexible; limited applications; and optimized for batch computing in an interactive world. Proponents argued the positives: reliability; scalability; efficiency; security; and control.
Reinventing the wheel – without end
Mainframes were expensive because they were a) low-volume products and b) had high (60%+) gross margins. Each mainframe architecture had its own processors, peripheral interconnects, networks, OS, application software and sales and support groups.
Every mainframe company had to solve all the problems every other mainframe company did – at enormous cost.
Mainframes are far from dead, but they are very different today. There are fewer vendors; they use commodity processors, networks and interconnects; run open source software such as Linux; and adjusted for inflation they are much cheaper.
That is the future of big monolithic arrays.
Monolithic arrays tomorrow
That we still have as many large arrays and vendors is due to the fact that the vendors have already gone far down the mainframe path. Commodity server motherboards, Linux, SATA drives and Xyratex enclosures are all common in high-end arrays, helping cut costs.
But at a fast approaching point, cutting costs isn’t enough. Vendors have to give customers good reasons to keep buying the big iron. The traditional mantra of availability, performance, scalability and supportability won’t hold customers forever.
Moore’s Law keeps moving the tiers
The industry has been pushing tiered storage in multiple guises for decades: HSM; ILM; and now, cloud storage. But customers embrace tiers out of necessity, not love.
The powerful visual picture of the layer-cake storage pyramid is deceptive. The x and y axes are cost and capacity, but they are only proxies for the application requirements of the layer above.
Array vendors want to believe that there will always be an “array layer” in the storage pyramid. But why should there be?
As Moore’s Law keeps moving commodity server performance up, the performance envelope of commodity-based storage systems will enlarge. With the commoditization of 10GigE, flash, 6 and 12 Gbit SAS and a 10x increase in areal density, the bandwidth to exploit higher CPU performance will push today’s “archive” cluster storage into monolithic array territory. At a lower price, too.
The software that ties commodity hardware together will improve, weakening the availability argument. If performance is bandwidth driven, pNFS will close the deal for clusters. Scalability goes to clusters today and will only improve with time. Supportability isn’t owned by hardware companies – plenty of software-only companies have cracked the code.
Here’s the future storage pyramid
Won’t arrays disappear?
No, but they will change. For example, they’ll look a lot more like cluster storage under the sheetmetal and GUI. Flash will be an integral part of the architecture – and not as a disk drive. There will be less add-on software, because more will be built in.
Arrays will continue to support legacy interconnects, such as FC and FCoE – remember, this is the future we’re talking about – and legacy OS’s that commodity-based storage won’t. Storage is a conservative part of IT and arrays won’t disappear.
The StorageMojo take
I was at DEC when the company was growing fat selling VAXen. Many predicted that PCs would be the death of the minicomputer companies, but it took 8 years to hit DEC.
There is life after arrays. Minicomputers still exist – and are selling more than ever – but the business model is totally different. The loss of 30 gross margin points forced the issue.
Storage requirements will keep growing. But the days of 60%+ gross margins are drawing to a close. Survivors will follow classic military strategy: concentration of force; short supply chains; and clear objectives.
Courteous comments welcome, of course.