It also provides alternative paths from server to storage device. In other words, if a particular server is slow or completely unavailable, another server on the SAN can provide access to the storage device. A SAN also makes it possible to mirror data, making multiple copies available. The high-speed interconnection that links servers and storage devices essentially creates a separate, external network that's connected to the LAN but acts as an independent network. There are a number of advantages to SANs and the separate environments they create within a network.
SANs also make it easier to conduct online backups without users feeling the bandwidth pinch.
Another reason SANs are making big waves is that all the devices can be centrally managed. Instead of managing the network on a per-device basis, storage can be managed as a single entity, making it easier to deal with storage networks that could potentially consist of dozens or even hundreds of servers and devices. The interconnection of choice in today's SAN is Fibre Channel, which has been used as an alternative to SCSI in creating high-speed links among network devices. Fibre Channel was developed by ANSI in the early 1990s, specifically as a means to transfer large amounts of data very fast. Fibre Channel is compatible with SCSI, IP, IEEE 802.2, ATM Adaptation Layer for computer data, and Link Encapsulation, and it can be used over copper cabling or fiber-optic cable.