Small form factor SSDs coming to change the data centre

Apple’s recent release of a new MacBook Air with solid state memory outside a disk casing and a new alliance to promote smaller flash disks are changing conversations about the role of solid state disk.

Apple is hardly the first company one thinks of as a data centre innovator, but when the company released the new MacBook Air last month, eyebrows were raised beyond the world of consumer electronics.

Interest was piqued because the new laptops use solid state disk (SSD), but don’t use a conventional disk housing.

As Apple puts it in its description of the MacBook Air flash storage:

“Typically, flash storage is housed in a package that’s the same size as a conventional hard drive. Yet the flash chips themselves occupy a very small portion of that housing. Getting rid of the hard drive enclosure and using only the parts that matter — the actual flash chips — frees up about 90 percent more space.”

We asked Apple to explain how the storage interfaces to the computer but, in true Apple style, received an initial statement from Apple PR that used some of the text quoted above and no response to subsequent inquiries.

A third party who has contact with an Apple tech support person has since indicated that this MacBook Air teardown is accurate in its assertion that the solid state memory connects through a custom PCIe housing and connects using Serial Advanced Technology Attachment (SATA). Storage industry observer Steve Foskett’s analysis makes the same assertion.

Apple’s new technology is not unique. Several vendors offer flash memory on PCI cards and market the devices as alternatives to conventional disks in servers. These vendors point out that these devices contain sufficient capacity to store substantial amounts of data, but are vastly faster than their magnetic cousins.

Hewlett-Packard has even taken the concept into a blade server, the most prevalent servers in a modern data centre, with a product called the IO accelerator.

Since the launch of the MacBook Air, support for small SSDs has gone up a notch as a consortium of vendors has formed to “Promote enterprise storage usage of PCIe SSDs, by enabling serviceability, high-availability, ease of integration, interoperability and scalability of Solid-State Storage.”

The new group comprises Intel, EMC, Dell, Fujitsu and IBM, and has named itself the SSD Form Factor Working Group.

This effort, in concert with Apple’s new device, makes it almost certain that SSDs small enough to a home in a blade server will become a reality. Apple has demonstrated that it is possible to use a small SSD of this type as primary storage.

In discussions with the storage community it has been suggested to SearchStorage Australia/New Zealand that a chassis full of blades equipped with this kind of SSD could rival a small conventional disk array for capacity. If virtualised into a pool of storage, such a collection of servers could even represent sufficient capacity for some demanding storage and computing applications, making arrays unnecessary.

Another outcome of smaller SSDs could be far smaller and denser disk arrays.

EMC’s Marketing CTO for Australia, Clive Gold, says SSDs’ role is definitely changing.

“We agree that storage systems will change form factor, but this is a generational issue and as well the problem gets simpler when we have a two tier model when flash becomes more cost effective than the fast drives of today, thus leaving us with fast flash and bulk mechanical.

Gold also sees “Server flash as a cache, primary storage or part of the storage infrastructure,” but says he is more interested in “the future role of flash technology in the server! Today we are playing ‘horseless carriages’ - we've swapped out the mechanical drive for flash as the primary storage. But consider a 'cloud' world, where you are connected all the time, if I can run a smart piece of code that uses this large cache and keeps it coherent with my storage infrastructure, (something like [EMC’s high end array] V-Plex), then I have a new computing model. Here I could get a very low latency connection to my data, plus I have it secured in my 'private cloud', plus I don't have the single point of failure problem that the server represents.”

IBRS Analyst Kevin McIsaac makes similar predictions.

“SSD in VM clusters as a storage cache, you bet,” he wrote in an email to SearchStorage ANZ. “However there are barriers to adoption, mostly about how this is integrated with the storage array. I suspect long term, we get rid of storage arrays, the disk lives in some of the Intel servers in the cluster, and the cluster treats all the disk across all machines as a distributed storage infrastructure.”

“I think in the long run the array goes away,” he added. “They become just another Intel server in the VM cluster, stuffed with disks but they are a first class member of the Intel cluster.”

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