The SAN storage area networking

You can’t help but love those acronyms. (Yeah, right.) SAN stands for storage area networking.

Storage area networking would be... a network for a storage area? You’ve got it!

Specifically, a SAN is a network whose only function is file storage. The SAN network uses a high-speed protocol called fibre channel in order to transport data. So now, instead of having a NAS, or one box for file storage, we have a whole network dedicated to holding those files. Your regular network would be connected to the SAN but separate.

On paper, it’s brilliant—a network specifically designed for file storage only! Most importantly, it gets rid of the bandwidth problem. You can access the files without dragging fat chunks of data through your production network. To the client computers, file access will appear the same as if the files were actually hosted on file servers. However, each server is connected to the SAN, and the server’s purpose here is simply to facilitate the files that are being stored on the SAN.

A SAN has a number of advantages:

• It greatly reduces network bandwidth. All the bandwidth that was being used for backups and restores now gets transferred completely to the SAN.

• It allows storage devices access to all the files in the SAN. On a regular network, the storage device (like a tape drive) would be limited to the files found on the file server. Therefore, you might need one storage device for every file server.

• It allows quick file access for any client whose server is connected to a SAN, regardless of operating system.

Backups and restores have no detrimental effect on your production environment. The backup software directly accesses the SAN, not any computer in the regular network. Therefore, network bandwidth is completely unaffected.

All right, so let’s get a SAN now! We’ve found the answer!

As usual in the computing world, there is no one answer or absolutely fantastic solution with no caveats.

The problem with SANs?

• SANs are considerably more complex than other solutions. In fact, it is the most complex of all storage solutions listed here, requiring administrators to learn about SAN technology and increasing the level of their responsibility.

• SANs require a significant economic investment. Each device connected to the SAN, from servers to storage devices, needs to have a hardware interface specific for the SAN. A SAN requires fibre channel switches and hubs. It also requires a network topology entirely separate from the main network.

• A SAN solution may require you to acquire all the SAN components from the same vendor in order for the thing to work. Being obligated to buy everything from one vendor is usually an expensive way of running a business.

To sum up, complexity + dependence on one vendor = lots of $$$$.

For backup purposes, the SAN is a great proposition. Besides having the file access advantage that a NAS has, a SAN also removes all the network bandwidth issues that a backup or restore can create on a regular network. No longer does a major backup have to clog up precious network resources. However, as with any solution, you have to weigh the advantages against the costs. Is it worth it for your company to invest that much in a SAN solution, or can you meet your goals with a less complex (and therefore, less expensive) solution?