Three ways to approach SAN deployment

by Barry Mattingly

As a storage professional, you know storage can no longer be relegated to the backwaters of IT planning. According to Farid Neema, president of Peripheral Concepts, a storage market research firm in Santa Barbara, CA, enterprise storage requirements are growing at around 60% annually. In the NT environment, according to Neema, growth is running in the 80% to 85% range.

No doubt, you've been following all the hype and promise of the latest innovation in storage architectures-storage area networks (SAN). You've convinced yourself that the basic enabling technology is in place. And you can see the benefits of shared high-speed storage and backup. It's time to plan how you're going to build a SAN infrastructure. So, what are your options?

Before you start worrying about SAN strategy, though, you've got to take a hard look at your business needs and data storage requirements. Storage infrastructure involves four fundamental elements: CPUs, disks, tape backup/restore capabilities, and network/interconnect technology. You need to factor in all these elements as you craft a plan. Do you have historical data that reflects recent growth rates? What information can your sales and marketing people supply to help you predict future needs? Is your company bringing new products or services to market that might cause a spike in storage demands? Are you moving toward a 7x24 environment that will impact what data must be available and how it must be backed up?

All fundamental questions, to be sure, but if you're thinking about implementing a SAN, now is a good time to step back and look at the big picture.

Having developed a clear vision of your storage needs for the next several years, you need to focus on the key SAN capabilities: availability, scalability, manageability, and flexibility. There are essentially three ways to go as you begin to explore a SAN implementation.

First, there's the simple plan. You can try to work with existing peripheral technologies and add a Fibre Channel network and functions such as server-less backup, implement SAN management software, and add some intelligence to your existing peripherals and host CPUs. And, you can build your SAN from a variety of vendors, with certain caveats.

This approach is probably the most budget-conscious, and may be the best way to go for smaller companies. For a relatively small investment and without taking a great leap of faith, you can bring in the "building block" components that make up a SAN. You can choose which segment of your business you want to put in a SAN environment without committing to a complete overhaul of your storage infrastructure. For example, you might choose to build a SAN to service just your email servers, or perhaps link several departments that need shared access to data in a SAN.

The downside? Depending on how you structure your implementation, you may find yourself locked in to a homogeneous environment. Your manageability and flexibility may be constrained due to interoperability limitations of the software or hardware that you choose. In this approach, working with an experienced VAR, systems integrator, or ISV during the planning phase will go a long way toward assuring a successful implementation.

One-stop shop

A second option for SAN implementation is to find a single vendor that offers everything you need under one roof. Under this strategy, you'll most likely have to replace your existing storage (and perhaps even system) infrastructure and build from the ground up using that vendor's components and software. In these situations, you'll most likely take storage management intelligence away from your host and peripherals and move it into a central controller or storage director, sometimes referred to as a storage domain server, which is administered with domain management tools.

Most large systems vendors are pushing this model. They can help you bring in a Fibre Channel infrastructure, systems, arrays and tape libraries that work together and provide scalability, manageability, and high availability. This approach minimizes compatibility issues, and maximizes support. However, flexibility is compromised because you're relying on one vendor.

In addition, the single source option is likely to be the most costly. In addition, you're locked into the SAN vision of the vendor you select. Since you're making a huge investment, you have to count on your vendor to continue to evolve and innovate in the storage arena. You don't want to have to start all over again three or four years down the road. And, with the furious competition to establish a SAN standard, you can't be sure that the option you choose today will be a viable one tomorrow.

Bottom line: The single source approach is a viable option primarily for upper midrange to large corporate environments with deep pockets and plenty of staff.

If you need a lot of choice, support for a heterogeneous environment, and competitive cost, then you might investigate a third group of vendors, which are bringing products to the SAN market with a more "open-systems" attitude.

This approach addresses the fact that many shops already have a mixed vendor environment and would prefer to stay that way. These shops want to protect their existing hardware and software investments. They want the ability to pick and choose between components that interoperate seamlessly. They want a storage strategy that takes advantage of the heterogeneous operating systems they have by combining multiple operating systems and applications packages into one flexible, interoperable framework.

There are a number of vendors who believe that SANs can and will be built in a "plug-and-play" fashion and are working to create the standards and partner relationships to make this approach a reality. Organizations such as the Storage Networking Industry Association (SNIA) and Fibre Channel Industry Association (FCIA) are working to accomplish this goal. SAN component manufacturers and suppliers, as well as ISVs and VARs, have taken an active role within SNIA and FCIA, and have demonstrated open-systems SAN compatibility at interoperability "Plugfests" and similar industry forums.

One burning issue with implementing SANs in an existing IT infrastructure is preserving investments in existing SCSI-based storage hardware. To this end, a number of vendors offer bridge controllers (or routers) that provide the ability to attach most SCSI peripherals to a Fibre Channel SAN. And specialized SAN controllers are available to provide bridging capability as well as the intelligence required to share storage in a heterogeneous environment (i.e., among mixed SAN and non-SAN attached servers or heterogeneous hosts).

SANs represent the future of high-availability, high-reliability data storage. Early adopters have already built SANs that are providing value and competitive advantage to their end users. Some would argue that SAN technology is not yet mature, but components like Fibre Channel switches, SAN management software, intelligent disk controllers, and flexible, heterogeneous tape servers will only get better and more robust. The time to plan is now. The method you choose to bring a SAN into your company will depend on your business projections, your existing infrastructure environment, and your budget.

Barry Mattingly Tape Laboratories Inc.,
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Barry Mattingly is director of business development at Tape Laboratories Inc. (TapeLabs) in Los Angeles, CA (www.tapelabs.com).


This article was originally published on January 01, 2000