Introduction To Unified NAS & IPSAN In Comparison With FCSAN

By S.Gopinath, SANAT Technologies

Approach towards networked storage started in the 1980s with the introduction of Network Attached Storage devices and continued later in the 1990s when Fibre Channel (FC) emerged as an alternative method of connecting storage. FC could be used in either a loop technology, with up to 126 devices attached to a loop, or in a fabric with switches connecting multiple file servers and storage devices. This removed the direct connection between file servers and storage, allowing storage to be networked with multiple file servers sharing storage devices on a Storage Area Network (SAN).

Network storage was developed to address the challenges inherent in a server-based infrastructure such as direct-attached storage. Network-attached storage, or NAS, is a unique purpose device, comprised of both hard disks and management software, which is entirely dedicated to serve files over a network. As we are aware that, a server has the dual functions of file sharing and application serving in the DAS model, potentially causing network slowdowns. NAS relieves the server of storage and file serving responsibilities, and provides a lot more flexibility in data access by virtue of being independent. Another important consideration for a medium sized business or large enterprise is heterogeneous data sharing. With DAS, each server is running its own operating platform, so there is no common storage in an environment that may include a mix of Windows, Mac and Linux workstations. NAS systems can mix into any environment and serve files across all operating platforms. On the network, a NAS system appears like a native file server to each of its different clients. That means that files are saved on the NAS system, as well as retrieved from the NAS system, in their native file formats. NAS is also based on industry standard network protocols such as TCP/IP, FC and CIFS.