What is a SAN
?"> A Storage Area Network is a special purpose high-speed network that provides direct connections between storage devices (which henceforth will be referred to as "targets") and servers (often referred to as "initiators" in the storage world). In todays current marketplace, SANs are almost synonymous with Fibre Channel, a computer, storage, and network device communications protocol designed for high performance information transfer that is capable of high bandwidth (100MB/s and beyond), flexible topologies, and connectivity over several kilometers.
First and foremost, it is extremely important to remember that a SAN is indeed a network and that, over the course of its evolution, the SANs seen in IT organizations will contain a mix of networking connectivity options, including Fibre Channel, the emerging iSCSI, and the Fibre Channel over IP standards like iFCP. Since the vast majority of software and hardware for SANs are Fibre Channel based, we will focus on the benefits and limitations of current fibre channel based SANs in this article.
The advantages of a SAN include: improved performance via the use of storage networking hardware thats faster than traditional server-attached storage, and improved accessibility and scalability of storage resources by permitting users to access those resources through multiple servers. They also make it easy to add storage and servers without downing the network, and more importantly, they provide redundancy.
|"The goal of a SAN is to integrate different types of storage subsystems such as high-throughput RAID, high-transaction rate RAID, near-line long-term archival storage, and short-term backup storage into a single system."|
The goal of a SAN is to integrate different types of storage subsystems such as high-throughput RAID, high-transaction rate RAID, near-line long-term archival storage, and short-term backup storage into a single system. SAN resources are made available to users through partitioning or through a single shared file system. A SAN can also enable direct storage-to-storage interconnectivity, and allows administrators to exploit new breeds of clustering technology and intelligent device sharing to provide disk storage and tape backup services to one or more servers.