Storage Area Networks

The need for storage devices is growing by leaps and bounds. In addition there are a number of options available depending on specific storage requirements. There are numerous options available with SAN.

The two most popular variants are Fibre channel (FC) and Internet Protocol (IP). In a FC SAN the disc arrays are connected using fibre channel connections. An FC switch acts as the central point of control for data flowing through the SAN.

Hence, FC or IP depends upon the application. If the data is critical, Fibre Channel is a better option. A low cost SAN is an integrated package that includes an FC switch, high-performance software and disc storage that can be hooked up to two servers.

An IP SAN uses the internet small Computer System Interface iSCSI protocol and Gigabit Ethernet over Cat 6 cabling to hook up disc arrays over a Transmission control protocol / Internet protocol (TCP/IP) network. These SANs provide native-level block access and data transfer and are similar in this respect to traditional FC SANs. Essentially a customer data centre requires various transport technologies that enable long distance connectivity in a cost effective manner. Fiber Channel is better for high speed connectivity and applications such as ERP and databases.

For a small organization IP SAN would suffice. A judicious mix of both IP and Fiber Channel is required to balance cost and efficiency of storage systems and devices. NAS and SAN NAS is a data storage mechanism where the storage devices are connected directly to the network. These devices are assigned an IP address and then can be accessed by clients via a server that acts as a gateway to the data or in some cases allows the device to be accessed directly by the clients without any intermediary. Easy manageability is a important feature of NAS.

It is focused on simple file serving needs. NAS and SAN are complimentary to each other. The trend is towards hybrid solutions. SAN can be used as a back end and NAS as the front end ie having a NAS header in a SAN environment. Large organizations with enterprise networks and a wide geographical spread are opting for SAN whereas small and medium businesses find NAS a better option. In SAN there is a movement towards IP because one can use the same protocol as the network leading to a lesser cost of implementation.

Growth in chassis ?based SAN switches is faster than in the fabric switch segment because of SAN and storage consolidation and linking of first generation SAN islands. Also ,the need to implement SAN extension solutions for data replication and business continuity is driving the need for intelligent multilayer SAN switches and related products. Ultimately the choice between San or NAS depends on a number of factors.

The cost of implementation, ease of maintenance, fault tolerance and security are some of the aspects which have to be considered while adapting a particular storage system. It is also possible to have a hybrid system with both SAN and NAS being used simultaneously. . One fit all is no longer feasible and the trend is towards a mixed bag of options. Copyright (c) 2007 Dean Barnard.

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