A storage area network (SAN) is a dedicated high-speed computer network that connects storage devices with servers. SANs can deliver shared pools of storage to multiple servers, on or off premises. Each server accesses the shared storage as if it were a drive directly attached to it. A SAN moves IT storage resources off of the user network and reorganizes them into an independent, high-performance storage network. SANs provide block-level storage, typically via a Fibre Channel connection. They require proprietary hardware, making them more expensive to scale than software-defined storage (SDS) or cloud-based solutions.
A storage area network typically includes cabling, host bus adapters and switches attached to storage arrays and servers. Each switch and storage array on the SAN must be connected, and the physical connections must support bandwidth levels that can handle peak input/output activities. Storage arrays may be hard disk drives or flash solid-state drives. Organizations use SANs for distributed applications that need fast local network performance. In addition to storing data, SANs allow automatic backup of data and monitoring of storage and backup process. The main benefit of using a SAN is that storage can be treated as a pool of resources that can be centrally managed, tiered and allocated as needed.
SANs are highly scalable because capacity can be added as required. They improve the availability of applications through multiple data paths, and because SANs can span multiple sites, they improve business continuity. The main disadvantages of SANs are the cost and complexity of proprietary hardware and software. Organizations that need to store large amounts of unstructured data (such as email messages, presentations, documents, graphics and media files) often use a software-defined storage solution to scale out storage capacity as needed. An SDS solution like SUSE Enterprise Storage provides unlimited scalability. It can run on Linux and in a virtual machine, on premises or in the cloud, using off-the-shelf hardware.