Storage Area Network

SANs are normally built on an infrastructure specially designed to

handle storage communications.

Storage Area Network (SAN) is a high-speed subnetwork of shared storage

devices with associated data servers. Network is designed to attach storage

devices such as disk array controllers and tape libraries to multiple servers,

multiple paths are used to connect servers and storage systems

In a storage network, a server issues a request for specific blocks, or data

segments, from specific disk drives. This method is known as block storage.

The device acts in a similar fashion to an internal drive, accessing the specified

block, and sending the response across the network.

SAN's architecture works in a way that makes all storage devices available to

required servers on a LAN or WAN. Because stored data does not reside directly

on any of a network's servers, server power is utilized for business applications,

and network capacity is released to the end user.

Basic Architecture of SAN is depicted below

Below is the layout of Enterprise Class HP SAN EVA

image copyright : hp

Main Components of a SAN

Drive Enclosure --1

SAN Switches --2

Controler Enclosure --3

Controller Enclosure : A pair of two interconnected controller modules that

control the physical disk array

Controllers : A hardware device with its own firmware that connects to the

Physical Drives and makes them available to host servers, also called as

array controllers