"In the last five years, applications running on servers have become critical to businesses. But we end up with with too many data touch points to manage efficiently. The solution is to install a Storage Area Network. For many businesses iSCSI is the way to go." David Dale, industry evangelist at Network Appliance.

Once, long ago, all your company's data fit nicely on a single file server. Then, individual departments demanded their own servers. Given how cheap Wintel boxes had become, how could you refuse? Then you added a database server for Oracle data, another for SQL. Next you installed an Exchange server to rout mail to work-at-home PCs and roving laptops.

Pretty soon, the IT managers are popping antacids. But help is at hand.

"In the last five years, applications running on all these servers have become critical to your business. But you find yourself with too many data touch points to manage efficiently," says David Dale, industry evangelist for storage vendor Network Appliance Inc. (NASDAQ: NTAP) of Sunnyvale. "The solution is to install a Storage Area Network."

Storage Area Networks (SANs) provide centralized storage arrays that are accessible to any and all servers on a network through a high speed LAN or WAN connections. Placing storage in a centralized location simplifies backup, makes management and replication of data easier, and lowers costs considerably.

But to make a SAN work, you must provide a fast connection between disks and servers. Until recently that meant installing a specialized fiber channel network. Fiber channel connections use expensive proprietary technology priced way beyond what most small businesses can afford.

In 2003, the Internet Engineering Task Force standards group ratified a new type of SAN connection designed to bring SANs to the masses. Dubbed Internet SCSI (iSCSI), this new standard eliminates the need for high-priced fiber channel networks and allows SANs to be connected via existing fast Ethernet networks. Now that many of the kinks have been shaken out, analysts are acclaiming iSCSI as a disruptive technology -- one that stands to radically alter the high tech landscape.

By 2004, the market for iSCSI SANs passed the $100 million mark. IDC (NYSE:IDC), the market research firm from Framingham, Mass., predicts that iSCSI-based sales will triple in 2005 to $307 million, jump to $700 million in 2006 and reach $1.5 billion in 2007.

Not all iSCSI SANs are alike

Most early iSCSI installations were by large companies with existing fiber channel SANs who used iSCSI to fill niches that did not warrant full fiber. Leading fiber SAN vendors, such as EMC Corp. (NYSE: EMC) and Network Appliance, added iSCSI support to existing fiber SANs to meet this market need.

Larger storage vendors often strip features from iSCSI solutions so as not to compete too closely with their own high-margin fiber channel solutions. But that is likely to change as iSCSI products from startups such as LeftHand Networks Inc. of Boulder, Colo., and Sanrad Inc. of San Mateo become better known.

At the other end of the scale are cheap iSCSI-specific SAN systems targeted at the mass market. For example, for $10,000 and change you can buy an Adaptec Snap Server 18000 SAN with 2 terabytes of storage. These may be simple to install and easy to manage remotely but they are not lightweights. The 18000 can be scaled up to 30 terabytes by plugging in new drives and when used with 10 gigabyte Ethernet switches provide very respectable performance.

Steve Rogers of Adaptec Inc. (NASDAQ: ADPT) of Milpitas says it makes sense for small businesses to start small and upgrade when needed. "All PCs and servers these days ship with built-in Ethernet cards. Current operating systems include free iSCSI initiator software. These two pieces are all you really need to tie into a networked iSCSI SAN. The penalty you pay with this approach is that your CPU processes the iSCSI stack. If you have cycles to spare, this may not be much of a problem. You can eliminate any serious choke points by investing a few hundred dollars in a specialized iSCSI network accelerator card called a TCP/IP offload engine (TOE). The TOE takes over the job of stack management and releases cycles back to the CPU."

The same approach holds true for investing in multi-pathing Ethernet solutions, cluster support, integrated enterprise backup, and next-generation data services. You may not need all these features today, but if you plan ahead, you can add essential features tomorrow as upgrades rather than by replacing the hardware you are buying today.

Joe Devlin is a freelance writer based in the San Francisco Bay area.