Analysis & Commentary:

SECRETS OF THE SAN

Just a decade or so ago, when having a 1 GB PC hard drive seemed the height of computing sophistication, the majority of enterprises employed simple methods to collect and classify their data.

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Those firms that no longer relied on archived paper and microfilm had moved on to storing information using direct-attached storage devices hooked up to a single computer server. If they filled up that device or decided they needed a second backup copy, they would acquire another drive to fill the gap.

But with the exponential increase in the volume of storable information, relying on direct-attached storage became cumbersome and expensive in terms of both hardware and manpower. IT managers needed to find a way to consolidate and manage data in a cost-effective and secure fashion.

Enter the storage area network, or SAN.

SAN Hardware

Dan Tanner, a storage and storage management analyst at the Aberdeen Group, said that a SAN consists of peripheral storage connected to servers throughout a switched network.

In a basic SAN setup, server computers act as centralized hosts for directors, which typically are fiber channel adapters that transmit signals back and forth between servers and outlying devices.

Also present are switches, which determine the path for dispatching information throughout the network, and storage subsystems with hardware RAID (redundant array of independent disks) controllers.

SAN Software

A SAN uses logical unit number (LUN) management software to help IT managers identify individual hard disks within a RAID setup. It also uses remote mirroring software, which writes two copies of stored information on separate drives to safeguard an enterprise in case one of the devices fails.

Finally, the SAN uses point-in-time copy software, which makes either a physical or virtual copy of an enterprise's stored information at a given moment and stores it in case anything affects the dynamic version of the company's data.

Aberdeen analyst David Hill said point-in-time software is important to a SAN because it acts as a snapshot of a company's data.

"Let's say that at 1 p.m., I make a copy of my data to store onto another set, [which] remains frozen in time," Hill said. "If a virus hits the server at 2 p.m., I can then at least reference the [data saved at] 1 p.m."

The Hard and Soft of It

Hill explained that two primary "hard" reasons compel enterprises to install and deploy SANs: a need to consolidate storage and a need to improve software backup management.

"When you consolidate and manage storage in a central pool, there is a better overall utilization of [it]," Hill said. "And because the data is centralized, enterprises can avoid adding additional managers to run the system, making it more cost-effective."

Hill added that three additional factors, which he termed "soft" reasons, typically drive enterprises to use SANs: improved manageability, availability and flexibility of information storage.

"Organizations probably select at least one 'hard' reason and more than one 'soft' reason," Hill wrote in a recent white paper. "Hard reasons are the required results, and soft reasons are the optimal optional desired results."

Key to a Successful SAN

While many variables, including environment, cost issues and prior purchasing habits, determine the best SAN setup for a particular organization, one factor is essential to implementing a successful SAN.

"Make sure it's interoperable," Hill said.

Within this parameter, an enterprise has the option to set up a homogeneous SAN (in which all servers run the same operating system) or a heterogeneous version, in which servers that use different operating systems -- such as UNIX and Windows NT/2000 -- are connected.

Big Players

According to Giga Information Group analyst Rob Enderle, the big players in the SAN space right now are EMC, Hitachi and IBM.

Aberdeen analyst Hill said those three companies often will purchase some of the components required to build their systems from such companies as switch manufacturer Brocade Communications Systems and maker of data traffic directors McData.

The heightened data security environment, especially since the events of September 2001, has boosted awareness of the critical nature of effective data storage.

It stands to reason that as the volume of available information continues to expand in parallel with increasingly stringent security considerations, the SAN business is likely to generate significant profits for all players in the sector.