Storage area networks (SAN) are attractive to many enterprises looking to rationalise their spending on storing data. But there was one overriding problem initially that limited their adoption: SANs need highly skilled, expensive SAN consultants and managers to make them work, making judicious choices in their suppliers, hardware and software. The biggest obstacle was getting different vendors’ equipment to work together, something that was frequently impossible.

The last few years have changed this situation considerably. Through groups such as the Fibre Channel Industry Association (FCIA) and the Storage Networking Industry Association (SNIA), vendors have been able to make connecting SAN hardware together far easier. This has brought about considerable acquisition-cost benefits.

“The price advantages of being able to acquire kit from multiple vendors have been very enticing,” says Andrew Manners, head of UK storage for Hewlett-Packard. “Once people have bought SANs and got them working, they’ve loved them so much they’ve bought four or five. But they haven’t stuck with one vendor because there’s such a cheap entry point and vendors have been doing deals that make it even cheaper.”

In addition, says Jon Pavitt, EMEA storage services director at Unisys, organisations have tended to invest in SANs for individual projects; each project has simply bought a new SAN rather than brave internal politics and the organisational requirements necessary to increase the storage of an existing SAN.

But managing those different pieces of hardware, particularly from a single console, has proven a far greater challenge. In the majority of cases, vendors’ own storage management tools were capable only of managing and monitoring their own equipment using proprietary APIs. Third-party software vendors such as Veritas, now part of Symantec, were able to provide their own storage management tools only by tapping into these numerous APIs.

After several false starts and a long process that started as long ago as 1999, the storage industry has finally been able to agree on a set of management and control standards, SNIA’s Storage Management Initiative Specification (SMI-S), that make interoperability feasible for all vendors.

“SMI-S is the poster child of what SNIA has achieved,” says Matthias Werner of IBM-Switzerland who is a member of the board of SNIA. “It’s where the most benefit is: switches, disks, under a single point of control.”

SMI-S 1.0.2, the latest version of the standards, enables both discovery and some degree of management of storage arrays, switches and hosts without the installation of any software agents. Any hardware that obeys the standard – and the majority of new products now shipping do – should be capable of being managed by software that understands the standards, using the exact same interface; it can also be monitored, providing storage managers with detailed information such as temperature, power supplies, fan activity and capacity.

Guy Bunker, chief technology officer at Symantec, says this has many benefits for end users. “Standards offer the customers choice, which is something the hardware vendors are not particularly enthusiastic about. Without standards – and this is something Veritas suffered from – every management product has to understand every product it needs to manage. That discourages innovation from small companies.”

At the moment, Bunker says, the SMI-S standard offers 80% of the functionality needed for most organisations to monitor and control their SANs during their daily operations. The areas where the standards are lacking are in more advanced configuration, such as partitioning and mirroring functions. For these tasks, recourse to proprietary tools is still necessary.

However, Hamish Macarthur, CEO and co-founder of storage analyst firm Macarthur Stroud International, says that 80% figure hides other issues. “If it’s just about operating, then 80-90% is about right.”

But standards are no use when dealing with older, non-compliant hardware. Some vendors do offer shims that enable a standards-based management of older systems, but they are a minority. For many IT decision makers using proprietary tools is the only realistic option.

Different strokes

Interoperability of storage systems is also an issue. SNIA provides vendors with a certification suite that runs hardware through its paces using the standards; if the hardware responds as required, the vendors can then declare themselves compliant with the latest standards.

However, Matthew Brisse, technology strategist at Dell, points out this testing does not show whether the hardware interoperates with real-world software and hardware.

And with various different versions of SMS-I available in the real-world, version 1.0.2 being the most common in shipping products (more than 280 have now been certified) and 1.0 available in many just-shipped products, being sure of exactly what a piece of kit should be capable of doing using the standards can be difficult.

Jon Pavitt, who is responsible for Unisys’s storage offering, says that while virtually all vendors have signed up to the standards, they’re “not readily forthcoming” in providing interested parties with details of what hardware they’ve incorporated them into and which versions of the standards.  

The situation is mired in self interest, says Nigel Tozer, consulting manager at software maker, CA. “Some vendors try to play the game and apply the letter of the standard – just enough to get certified.”

Nevertheless, vendors are adopting the standards in ever-increasing numbers. And increasingly, SMI-S support is becoming an essential component of the purchase requirements, says Dell’s Brisse.

With industry momentum behind many of the storage standards, many more are planned. Helmut Beck, VP of storage at Fujitsu Siemens Computers, says his company is one of many supporting work in SNIA to develop standardised interfaces between back-up storage systems. These will include standards for fault management, storage security, copy services, policy management, tape libraries.

John Kelly, SNIA’s storage management forum vice chair, says the aim is to consolidate discovery, access, reporting and control features into a single, standard architecture that will establish a foundation for a broader set of management capabilities in the future.

And there are other standards efforts underway. The Aperi open source framework is an industry-wide initiative, launched in October 2005, to create a SMI-S compliant code library for storage management. Extensible Asset Management (XAM) is another SNIA initiative to bring standards to information lifecycle management and to create a standard interface between applications and storage.

Only the first steps have been taken with storage standards. Much more effort will be needed before heterogeneous SANs can be completely managed using a single standards-based console.

Indeed there is a risk that with storage developments out-running the slower moving standards-creation and ratification processes, interoperability could become entrenched.

But while movement towards ratifying standards and testing for conformity is slow, says Vincent Franceschini, senior director of future technologies for Hitachi Data Systems, it is essential. Business leaders are demanding a more flexible, responsive IT infrastructure: “That cannot be done with the silos that exist today.”

Further reading

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