I'm talking about storage virtualisation. After spending several years in relative serenity, this technology, which promises to make it easier to manage networked storage, became hot last year. The past 12 months saw key product announcements from vendors like IBM, EMC, Network Appliance, Hitachi Data Systems and Sun Microsystems.
Hot for vendors, that is. For a majority of enterprises, this technology is still at tire-kicking stage. But the bombardment of fiery marketing rhetoric has already started.
We have seen this before: a technology that suddenly becomes strategic (read: able to earn marketing points) gets reworked by vendors to suit their needs, leading to the terminology itself being twisted to fit the marketing pitch. It is the same with grid computing.
Not that the escalation in complexity and the debates are necessarily bad things. For one, it gives the market a host of choices. For another, this zinging in different directions gives us tech journalists lots of writing fodder.
In my old interview notes, I quoted a company executive at a Veritas press event in 2000, describing storage virtualisation as "a technology that hides multiple disks from servers joined to them, virtualising them into a single volume".
Of course, ask system admins who hark back to DOS days and they will tell you the technology was birthed by Redundant Array of Independent Disks (RAID), a now-defacto server disk technology that uses two or more drives to improve data access performance and reliability. RAID was a novelty then, but is now a staple, and rock-solid in definition.
But the subject of storage virtualisation will likely trigger philosophical debates today -- one of the biggest being where virtualisation should reside in a SAN: switch, subsystem or as a separate appliance? Another contentious point: what makes up a virtualisation recipe?
"Of course it means different things for different vendors," said Brocade CTO Jay Kidd.
So why virtualise storage at the network level? "The network is where you can extend storage services across multiple arrays," Kidd said. "You can also move data in the background (across different arrays) without taking an application offline, crucial if you have an array that supports, say, 200 applications."
Kidd feels that storage virtualisation should include data migration and data protection functionalities, above just presenting a single virtual volume to a motley bunch of physical volumes.
Come June, Brocade, together with SAN switch rivals Cisco and McData, will be ready to release switches that feature EMC's storage virtualisation software, called Storage Router. Re-directing data -- a function which, as Kidd pointed out, can be harnessed to achieve data redundancy and protection -- is, of course, what a switch does best. c Moving from the switch to subsystem camp and we have a different perspective. Hitachi Data Systems' Asia South product marketing/management Lim Beng Lay said that storage-moving functions like cloning is integral to the virtualisation recipe. HDS, of course, sells the TagmaStore Universal Storage platform, which spawns virtualisation commands from HDS' storage array controller, a place where one normally initiates heavy-duty data moving tasks like clone and mirror.
With controller-, or subsystem-spawned, virtualisation, Lim is also selling the notion of simplicity. "A big headache for companies today is the need to use many layers of software to run a SAN," he said.
Since TagmaStore resides in the storage controller, Lim reasoned that one naturally gets tight integration between storage virtualisation and core SAN functions. "You are effectively collapsing various software layers into one, and you don't compete and take away SAN array functions."
To highlight his point, Lim compares storage virtualisation outside the array as akin to "using a horse to pull a car", where the car is the storage controller. "Why would you do that?" he asked. "You don't consolidate software around a storage virtualisation appliance."
But a storage virtualisation appliance is what NetApp is selling in its gFiler. Last December, NetApp made a great of deal of marketing noise when it upgraded the kernel of its gFiler virtualisation product, and announced roadmaps that will see gFiler merge with that of Spinnaker Networks, a company NetApp acquired in late 2003 for its large-scale clustering file system technology called Spin FS.
Also in the appliance mold is IBM's SAN Volume Controller (SVC), which received an update two months ago. The highlight of the latest SVC is the fact it now supports the virtualisation of EMC arrays. Like the gFiler, the SVC is a drop-in appliance. The SVC, however, can also run on the Caching Services Module (CSM) for the Cisco 9500 or 9216 switches.
Which brings the debate back to EMC's Storage Router. With its new technology, EMC now trumpets another facet of storage virtualisation: interoperability.
The common link to the EMC, Brocade, McData and Cisco alliance is a low-key storage API standard called the Fabric Application Interface Standard (FAIS). Watch out for FAIS gaining a higher profile this year when it's ratified by the American National Standard Institute's (ANSI) T11 Committee.
Storage Router is all about -giving choices" via a standards route, said Ken Steinhardt, EMC's director of technology analysis. -FAIS gives us the ability to integrate into whatever the customer chooses at that middle level of the network -- whether Cisco, Brocade or McData," he said.
-So a fundamental difference between EMC and (HDS and NetApp) is that we are not trying to re-invent the existing intelligent switching software already present in the market by creating our own dedicated in-band virtualisation device," Steinhardt said.
-We don't want to deliver proprietary solutions," he added.
Of course, no vendor likes to claim unfriendly solutions these days. But it will take some time before storage virtualisation becomes as friendly as RAID.
When will that happen? Perhaps when the term storage virtualisation gets only cursory mention in product specification -- ala RAID today. You know when a technology is relegated down a specification sheet, it has become truly industry standard.
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