Storage Area Networks For Dummies

by: William Hauselberg

A Storage Area Network (SAN) is a collection of storage devices that are tied together via a high-speed network to create one large storage resource that can be accessed by multiple servers. SANs are typically used to store, share and access enterprise data in a more secure and efficient manner compared to traditional dedicated storage models. With dedicated storage, each server is equipped with, and uses an attached storage capability. A SAN meanwhile basically acts as a common, shared storage resource for multiple servers. The storage devices in a SAN can include disk arrays, tapes and optical jukeboxes all of which can be accessed and shared by all of the attached servers.

How a Storage Area Network Works

In a storage area network, the pooled storage resources and the servers that access this storage are separated by a layer of management software. The software allows IT administrators to centralize and manage multiple storage resources as if it were one consolidated resource. Because of the software, each of the servers sees just one storage device, while each of the storage devices in the SAN sees just one server. Data can be moved at will to any of the devices on a SAN.

Factors Driving SAN Adoption

A variety of factors have been driving enterprise adoption of SAN architectures over the past few years. One of the biggest factors has been increased cost-efficiencies. Storage area networks allow companies to optimize the utilization of their storage resources. With an attached storage disk, any extra storage capacity on that disk would remain unused because no other server could use it. With a SAN on the other hand, all memory resources are pooled, resulting in better usage of existing capacity. Since SAN’s allow data to be moved freely, enterprises can also move old and outdated data to inexpensive storage devices while freeing up the more costly devices for more important data.

Storage area networks make it easier for companies to expand their storage capacity, add resources on the fly, allot additional resources to an application, and maintain systems far more easily than traditional storage technologies. In addition, SANs allow companies to swap out a disk or tape-drive more easily and enable faster data replication. Importantly, SAN architectures allow storage devices from multiple vendors to be tied together into a common shared storage pool. Another advantage of SAN architectures is that they allow the storage network to be located at long distances away from the server hardware, thereby enabling greater disaster recoverability.

SAN Security a Big Concern

Despite such benefits, there are some caveats associated with the implementation of SAN architectures. Storage area network security is by far the biggest issue that companies need to do deal with when moving to a SAN storage model. With a SAN, companies are literally putting all of their most important data in one central resource. As a result the need for security controls such as firewalls, intrusion detection systems, SAN encryption and network monitoring are greatly heightened.