A Storage area network, or SAN, is a high-speed network of storage devices that also connects those storage devices with servers. It provides block-level storage that can be accessed by the applications running on any networked servers. SAN storage devices can include tape libraries, and, more commonly, disk-based devices, like RAID hardware.
SANS simplify some management tasks!
SANs are particularly helpful in backup and disaster recovery settings. Within a SAN, data can be transferred from one storage device to another without interacting with a server. This speeds up the backup process and eliminates the need to use server CPU cycles for backup. Also, many SANs utilize Fibre Channel technology or other networking protocols that allow the networks to span longer distances geographically. That makes it more feasible for companies to keep their backup data in remote locations.
Utilizing a SAN can also simplify some management tasks, potentially allowing organizations to hire fewer IT workers or to free up some IT workers for other tasks. It's also possible to boot servers from a SAN, which can reduce the time and hassles involved in replacing a server.