Storage area network (SAN)
A network which is created by attaching storage devices such as disk arrays and tapes to a common server so that the storage devices appear to be confined to operating system is known as storage area network.
How SAN Works
Data in SAN (Storage Area Network) can be stored using two basic modules as DAS (Direct Attached Storage) and NAS (Network Attached Storage). DAS is so named because it is a directly attached to a server without any intermediary network involved. Main distinguishing character of DAS (Direct Attached Storage) is its direct connectivity through a host bus adapter without the use of the networking devices as hubs, bridges and switches. In a network attached storage system, many independent clients can access the storage memory. The aim of the NAS (Network Attached Storage) is to provide only file based storage devices. DAS (Direct Attached Storage) can also provide multiple and parallel access if we equip this network with multiple ports. In the same way we can convert NAS (Network Attached Storage) to a DAS (Direct Attached Storage) by disconnecting the entire network and attach the port to a single computer. DAS (Direct Attached Storage) can be termed as an inefficient network because it cannot share its idle resources with other units in the network. DAS (Direct Attached Storage) and SAN (Storage Area Network) can overcome this deficiency but both these networks are costly and difficult to handle. Main DAS (Direct Attached Storage) protocols are SATA, SAS and fiber channel.
Infrastructure of SAN (Storage Area Network)
The basic infrastructure of SAN (Storage Area Network) is based on fiber channel fabric, which is mainly designed for storage devices. This channel provides more steady and speedy access. In a LAN network segment each device in a network share the same physical layer. Fiber channel fabric also serves the same purpose. A typical fiber channel fabric comprises of many fiber channel switches. In order to develop a smooth and efficient SAN (Storage Area Network) architecture many fiber routing solutions are becoming popular. These enable the data to come across fabrics without integrating them. Initially there were no attuned hardware devices for fiber channel fabric. Many vendors have now provided viable solution for this incompatibility.
Benefits of SAN (Storage Area Network)
San allows the sharing of storage devices, and releases the user from the hassle of carrying physical cables and other storage devices. Servers can boot from SAN (Storage Area Network) on their own. This allows the replacement server to make use of the logical number unit of the defective layer. SAN (Storage Area Network) was initially really expensive that even major multinationals were afraid of employing it. Nowadays the cost of SAN (Storage Area Network) has dropped to a level that even some small organizations are using direct attached storage. It has become easier to establish a SAN (Storage Area Network) than to buy servers which have plenty of disk space. SAN (Storage Area Network) increases the disk utilization. When you develop a single storage network, you get the ease of handling files as single unit. This provides you the ease of dividing the central storage pool s to reside at the network level and enables you to allocate storage more conveniently and intelligently to the other servers that want it.
The initial cost of implementing any SAN (Storage Area Network) disaster recovery sytem can be huge, but its higher efficiency and quick results would cover the cost in no time.San uses very protective disk applications in order to make sure that that the data does not corrupt .the best part of employing SAN (Storage Area Network) is that you do not need to worry about upgrading it at regular intervals. One just has to aplly the SAN (Storage Area Network) system and forget about it would do the wonders itself. SAN offers centralized storage network , and its speed and efficiency is much more than the bundle of individual servers put togther to make storage network.hence it can be said that SAN (Storage Area Network) is a one time expense and easy to handle storage network.