Making the SAN decision Featured

7:00pm EDT December 26, 2007

As companies grow, so do their requirements for technology. As they outgrow servers and disk space, they must look for the best alternatives to assist their growth with the least disruption to their current business.

According to Richard Florence, director of professional services for Orange County-based Agile360, “The utilization of storage area networks (SANs) is becoming the solution of choice for many growing companies. A SAN combines the IT structures already in place with what is needed to accommodate current and future growth in a way that optimizes the entire IT operation.

Smart Business talked with Florence about the benefits of SANs.

What is a SAN?

A storage area network is essentially a separate computer network that connects storage devices to a heterogeneous set of servers on a many-to-many basis. SANs are typically comprised of network switches, disk arrays and some form of physical interconnect, such as fibre channel, SCSI or iSCSI.

What is the primary reason that a company might begin to look at using a SAN?

The main reason most companies introduce a SAN into their IT environment is that SANs provide IT managers the ability to manage their universal storage requirements from a central platform. When an IT organization purchases a server, the amount of disk space available for any application running on that server is limited by the size of the server and the size of hard disks available to that model of server. In many cases, disk space intensive servers, such as databases and file servers, face unpredictable growth due to company mergers or other changes in the business. As a result, the company must purchase a new server with greater storage capabilities once the available disk space of that server is exhausted. Often, the other computing resources on the server, such as memory and processors, are still capable of fulfilling their intended purpose. In the case of SANs, an increase in disk space requirements of an individual server can be addressed by simply adding additional hard disks to the SAN.

How else can the use of SANs enhance IT functions?

SANs can provide advanced functionality that usually isn’t available on servers without the use of third-party applications. Features such as data replication, mirroring and snapshots provide higher reliability to an organization’s critical data. Another popular advanced feature is the ability to move data across different levels of tiered storage based on factors such as frequency of use and file types. For example, there may be an accounting spreadsheet stored on a file server that has not been accessed in more than year. That spreadsheet would be automatically moved into a lower-performance, lower-cost disk array within the SAN infrastructure to ensure that the maximum amount of space is available for frequently accessed files on the portion of the SAN containing the faster, more expensive disk drives. Features such as this ensure that companies maximize their investment in storage.

What are some of the key considerations in the evaluation of a SAN?

Some of the critical elements of the SAN buying decision are high availability, performance and software capabilities. Since a SAN acts as a central data storage facility for multiple servers, it becomes a single point of failure for many of a company’s core business files and applications, so high availability of the SAN becomes the most critical concern in its selection. Features such as multipathing, which provides multiple data paths from the SAN to a server, and the use of multiple switching fabrics help to ensure reliability.

The performance capability of a SAN should also be examined using a ‘best-fit’ approach, whereby the speed and performance of the SAN should match its intended purpose. For example, a SAN that will be used to provide data storage for an e-mail archive system does not require the performance levels guaranteed by a fibre-channel, SCSI disk-based SAN. For that application, a SATA disk-based SAN usually meets the performance requirements and would be a less expensive solution. One must also look at the range of software available for use with the SAN to provide advanced features, such as data replication, mirroring and tiered storage functionality.

Are SANs suitable for small- to mediumsized businesses?

Yes, there has recently been a major push to create relatively affordable SAN solutions to accommodate the small- to medium-sized business. By utilizing newer technologies, such as SATA-based drives and iSCSI connectivity, some manufacturers have been able to offer SAN solutions in the sub-$10,000 price range. Many SAN manufacturers have also started to simplify the management of SANs to enable IT administration generalists to manage their environments without specialized training.

RICHARD FLORENCE is the director of professional services at Agile360. Reach him at or (949) 278-9532.