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During 2002, Benetton Group's consulting CIO Terry Phipps decided it was time to address a longstanding data storage issue, one that was having a detrimental impact on the clothing retailer's business. The company's satellite units across northern Italy, handling design, manufacturer, distribution, and other critical functions, were each sitting on their own 'islands of data'. Designers, for example, were unable to share their data directly with manufacturing for prototyping, and enterprise email was scattered over five separate sites.

Moreover, the storage infrastructure - largely direct attached storage (DAS) devices from IBM and Hitachi Data Systems - was the source of escalating expense, with the dispersed devices costing ever more to upgrade, maintain and manage.

Phipps' approach: to consolidate and connect. The company dispensed with the direct attached storage, and pooled data on a storage area network (SAN) at an IT centre at Benetton's headquarters in Ponzano. The SAN, based on Clariion storage systems from EMC, plus fibre channel switches and data replication software from specialist vendors, went live in September 2002. Even in its initial phase, the SAN has been used to consolidate product design, enterprise collaboration and email for 1,500 Lotus Notes users, inventory management, sales and financial information, and various data warehouses.

Benetton is hardly unique in wanting to go down this path. During the past three years, an estimated one-third to one-half of large organisations have implemented some level of storage networking. By pooling together their storage resources on a fibre channel-based SAN, they feel they can significantly reduce the cost of upgrading, or buying additional, DAS devices. SANs also help organisations to integrate data from different business activities via a centralised network. Furthermore, they promise to deliver much faster data throughput speeds than DAS, largely as a result of the two gigabit per second data transfer throughput of the fibre channel protocol.

In fact, IT directors, vendors and analysts all agree that SANs, at least as a concept, represent the future of enterprise storage.

But their experiences have not been all positive, as reflected in their unwillingness to go from proof of concept to company-wide implementation. As Meta Group analyst Phil Goodwin points out: around 55% of organisations have SAN/NAS systems in place, but only 30% of these are actually being used to store live data.

Rising slowly

The slower than anticipated adoption has been influenced by several factors. The downturn in IT budgets has not helped, with many companies finding it difficult to justify the upfront cost of moving to a SAN architecture - something not helped by the lack of return-on-investment case studies.

But, more importantly, the take-up has been influenced by the sluggish development of standards to enable devices from different vendors to hook into the same SAN. That affects the storage disk systems themselves, the software for backing up and moving the data around, virtualisation software for viewing the pool of storage as a single system image, provisioning software for allocating resources to meet the varying requirements of different applications and users, host bus adapters for transferring data between a computer's bus and the fibre channel hardware, and switches to pump data around the network.

"Companies often baulk at deploying a SAN because they have heard too many horror stories" [concerning non-interoperability]. Components are rarely guaranteed to work together," says Claus Egge, head of IDC's European storage division. He even knows of one European organisation that was sold the wrong set of host bus adapters by a SAN reseller. "If companies offering SAN technology cannot get it right, it does not bode well for those buying the equipment," he remarks.

To avoid such situations, the storage vendor community has been taking steps - albeit slow and piecemeal - towards product interoperability in recent years.

That is not helped by a tendency of organisations to over-commit to SANs. A mistake many companies make is that they are too ambitious when they first implement a SAN, says George Teixeira, CEO of SAN virtualisation software specialist DataCore. "Organisations often lose all rationality when they move to a SAN," he adds.

He explains that some organisations install products, such as application servers, fibre-channel switches and high-end storage disk systems on a SAN, without actually running connectivity tests between them. "It is hilarious how many times I have seen organisations not even get the switches to work with the application servers," says Teixeira.

What such SAN veterans recommend is a staged, project-based approach. Russ Holt, vice president at server specialist Dell's storage systems group, suggests that organisations start by connecting something like a departmental email servers onto a SAN.

They can then extend application coverage, as well as running more complex processes, such as data replication, automated storage resource management and virtualisation.

After connecting its groupware, email and data warehouses into its SAN, Benetton, for one, plans to consolidate new ERP applications into its networked storage architecture.

Another example is Oxford University's clinical research division, which in 2002 decided to make better use of its existing SAN. The Clinical School identified virtualisation software - which pools together storage capacity on a SAN and distributes it automatically to pre-configured application servers as they require it - as a mechanism for consolidating its storage and server infrastructure.

After a two month pilot phase, the University division went live with DataCore's SANSymphony virtualisation software. Connected to five of its application servers, SANSymphony has helped the division create a virtual pool of 1.5 terabytes of storage capacity.

Tim Shaw, the University's deputy director of networked systems, applauds the flexibility that the SAN has delivered. "To consolidate servers we have separated the storage from the application servers and virtualised the storage pool," he says. "This has enabled us to add more space as required, when required."

Shaw also expects SANSymphony to deliver significant cost savings and better utilisation of its storage resources. Before the implementation of its SAN, the Clinical School would often run out of disk space on some systems, while others had plenty of space left, says Shaw.

Of course, deploying and operating products such as virtualisation software on a SAN would be far easier if all the underlying devices worked seamlessly together. The reality is that the major storage systems vendors, supporting their vested interest in creating homogeneous storage environments, want to maintain tight control over which SANs their products will work with.

Interoperability interruptions

In response to criticism about how selective they are being in opening up their application programming interfaces, storage giants such as EMC now claim they are working to ensure their core storage management software is compatible with all its main storage systems rivals, including Hitachi Data Systems and IBM.

But users - and storage management software suppliers - want more action on open standards from all hardware vendors. Trying to address this situation, the Storage Networking Industry Association (SNIA) has developed the Storage Management Initiative Specification (SMIS). The initiative (formerly known as Bluefin) is intended to enable storage management software to be capable of working with all the leading storage hardware platforms.

But many vendors are sceptical of SMIS's potential. EMC chief technology officer Mark Lewis says, "It will take another two years for SMIS to be [fully] developed." And by then the vendors themselves will have established the ground rules for interoperability. "SMIS will be too little, too late," echoes Teixeira at DataCore.

Furthermore, storage software vendors claim their products' interoperability will offer significantly more functionality than anything SMIS will be able to deliver. A widely held view among vendors - most of which are also actively working on the SMIS standard - is that making SMIS a standard that will work across all the leading storage hardware platforms will result in 'the lowest common denominator of functionality'.

Where SMIS will probably play a much greater role is helping organisations discover and connect heterogeneous storage products on a SAN at the start of project, says Nick Tabellion, CTO of storage networking specialist Fujitsu Softek.

But the reality today is that there is no single centralised storage management console to manage SAN infrastructures, says storage analyst Bob Zimmerman at IT market research company Giga Information Group. Ominously, he adds: "A single, centralised storage management console [similar to existing systems management frameworks] will not be available for three to five years."

That is not something that most organisations feel they can wait for. The compelling arguments for SAN adoption - corporate-wide availability of data, efficient storage utilisation, responsiveness to changing business requirements - means the customers will force vendors to break down the barriers of complexity and cost much sooner.