Why storage area networks are set to succeed

Storage demands are doubling every two years and users still require easy access. As data management and storage become big business, the storage area network looks set to come out on top. Phillip Hunter reports

Storage is moving in the opposite direction to the applications it serves. While IT is moving out to end-users in the front office, storage is being pulled back into dedicated off-site locations, increasingly managed by third parties. The focal point of development is the storage area network (San), which has generic storage...

devices serving all IT applications, rather than specific operating system platforms and hardware devices. The San, running in parallel to the Lan or campus backbone, interconnects servers, hosts and storage devices.

There is currently a growth in off-site storage back-up services, and these are likely to embrace the primary data stored in Sans as well. In other words, enterprises will increasingly outsource the management and housing of their primary data to third-party service providers which can afford technology and premises that maximise the security and availability of information.

The key to this is affordable high bandwidth wide area communications, which is not quite with us yet, so an outsourced San is still for the future. Because of the role of networking, providers of San services are likely to include not just existing players in the storage, back-up and disaster recovery arena, but also telecoms and Internet service providers.

In the immediate future, though, Sans will be implemented in-house. Sun Microsystems storage marketing manager Chris Atkins says, "The San will disintegrate the concept of a storage supplier within the next couple of years."

In this sense, storage is aping the evolution of the workgroup Lan towards client/server computing, which divorced the operating system and applications from the hardware platform. Although users ended up being stuck with Microsoft software, at least they had a much greater choice of hardware supplier, and could mix and match within their networks.

Until now, this was not possible with storage systems, with enterprises usually dependent on a single supplier, which would also supply servers and other hardware. Indeed, of the big five storage system suppliers, four of them - IBM, Hewlett-Packard, Compaq and Sun - also manufacture general IT hardware. For these suppliers, storage is sold both as an integral part of IT systems, and also to third parties, which incorporate it in their total IT solutions.

EMC specialises purely in storage, although it has operated in partnership with other system suppliers. In fact EMC was an original equipment manufacturer (OEM) for HP. But now HP has decided that storage is such big business, and so strategic to its customers, that it must be involved directly. HP will still purchase storage systems and components from the likes of EMC, but now only via an OEM or sub-contracting agreement.

The San, however, will make it possible for enterprises to mix and match storage system suppliers, and this may give a boost to the makers of storage components and sub-systems. Seagate, for example, is the only supplier, apart from IBM, to manufacture all the components of a disc drive as well as the completed article, but unlike the latter does not sell complete systems direct to end-users. With Sans, suppliers like Seagate may start selling direct, injecting more competition and increasing choice.

The San also fits well with the trend towards integration of different islands of storage, which, according to IBM's storage systems divisional marketing manager Servio Resch, is one of the major driving factors in the storage business. "Many enterprises have islands of information and are now trying to consolidate them in a single device," he says. "The San is one solution for consolidation."

Some would say it is the only solution, but Resch points out that at present, perhaps just as an interim step, many enterprises are reducing their costs by implementing common management tools to administer disparate storage systems. This reduces some of the costs associated with training staff and configuring multiple systems, but does not go as far as a San because it does not eliminate all the overheads associated with having storage systems from different suppliers based on a variety of technologies. However, it is a step in the right direction.

GartnerGroup estimates that 80% of storage-related costs lie in management. Storage volumes are almost doubling year-on-year, outstripping the falling costs per megabyte, and total system expenditure on storage is increasing at the rate of 35% to 40% per year. This increases the incentive to cut management costs to offset rising expenditure.

This has not been achieved so far, but there is evidence that some enterprises have at least stemmed the increase, so that management costs remain static in the face of rising storage volumes. There is hope that Sans will deliver further relief on this front by eliminating the costs associated with managing disparate storage systems.

Cache demand

E-commerce is driving this rampant growth by creating demand for cached data that can be accessed rapidly by Web servers. It is also increasing the amount of customer-related data used for business intelligence applications.

Another factor is the proliferation of pervasive computing and mobile devices. While it is creating a new market for miniature storage devices, it is also increasing demand for central back-up storage.

Another significant trend is at the physical level of connecting storage systems to each other and to the computers or networks they serve. SCSI has been the established mechanism for connecting individual computers to storage devices, and is likely to remain so for the immediate future. But fibre channel has emerged as the favoured technique for interconnecting multiple storage systems and servers within a San. Unlike SCSI, fibre channel supports switching and can be used to interconnect multiple systems in a star-type network similar to switched Lans.

The typical enterprise network will look rather different in a year or two when Sans have become established. Servers and larger hosts will be interconnected via high-speed Lans, often based on gigabit Ethernet. Servers and hosts will be interconnected via a separate San to shared storage devices, rather than each having point-to-point links with dedicated storage systems. The San may be outsourced, with the enterprise having high-speed connections from in-house systems to the remote storage. In other cases, the San will remain in-house but be interconnected to a remote back-up or disaster recovery site. But a few enterprises will go the whole hog and outsource the lot, including their hosts and applications, to an off-site location managed by a third party.

Worldwide storage spend

1998 $1bn
2000 $4bn
2002 $9bn

Source: GartnerGroup

San and deliver

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