Storage Area Networks - Essay Example

Storage Area Networks History Data and information management has long been a dilemma for companies whose operational activities are largely dependent on humongous volumes of files stored either at client machines or servers on the network. Data management, in its short life, has had multiple paradigm shifts each creating new opportunities, challenges and room for further improvement. From the traditional management model of managing data on the local machines, the IT infrastructure organization and management took a new turn in 1990s with the introduction of the new client-server model, allowing multiple client machines to connect to a single server for data management, storage, backup and recovery operations. However, in client-server infrastructure methodology, management of information requires a strong local area network (LAN) with high bandwidth capabilities to allow for the transfer of heavy files. Recent years have seen an exponential growth in terms of disk storage capacities, extending now from Gigabytes (GB) to Terabytes (TB) and Exabytes (EB) of server data. The end of this millennium saw the arrival of some of the most extensive network storage management technologies, NAS, SAN and others. Network Attached Storage (NAS) A precursor of SAN, Network Attached Storage (NAS) is the term assigned to file servers, comprising one or more internal servers, preconfigured disk capacity with a specialized operating system for storage management. NAS servers become part of the network through traditional LAN configurations, allowing storage capabilities as file servers. [Figure 1 - Network Attached Storage] (Info Advantage) In terms of applicability, NAS servers have been designed to fit the needs of hosting data for web applications (Troppens). Since this storage technology has been developed specifically to assist in the sharing of files over networks, NAS provides the following advantages of its predecessors: 1. NAS functions using tailor-made or stripped-down version of the operating system suited to fit the needs of managing storage over networks. Due to this reason, NAS can be optimized to a larger extent than generic operating systems allowing for faster execution as compared to file servers based on generic operating systems. 2. As compared to storage technologies existent before NAS, it provides functions as snapshots, remote mirroring and backup over Fiber Channel SAN. 3. NAS servers allows for easy-to-use PnP (Troppens) file systems, allowing for greater optimization through removal of all functions not required in file serving, increasing storage capabilities in addition to low installation and maintenance costs. 4. NAS servers are easily scalable to suit the needs of an expanding organization A mere shortfall in NAS is its use of conventional network file systems such as NFS (Troppens) or CIFS in coordination with Internet protocols such as FTP or HTTP. This in turn limits the basic premise of file sharing paradigm, providing powerful performance against I/O intensive application requests. Successor to NAS - Storage Area Networks By definition, a SAN (or Storage Area Network) is "a specialized, high-speed network attaching servers and storage devices" (Tate). This new storage networking technology is so flexible that it eliminates the need for a dedicated connection between a server and a storage device, as well as the "concept that the server effectively owns and manages the storage devices". (Bird) SAN is preferred to a very large extent over other network storage capabilities due to a variety of factors; firstly, almost all traditional methods of handling high level of storage, accessibility and availability of sensitive and operational data have failed in wake of increasing requirements for fast and efficient transfers. Secondly, in comparison to a client / server model that supports server-centric data management operations, SAN facilitates the organization with a data-centric model making it possible to transfer large amounts of data without being dependent of the server. It plays a huge role in eliminating all the performance bottlenecks posed by traditional networks. Due to its data-centric model, it allows transfers as one of the following ways: 1. Server to storage (Tate) - The traditional cycle of requesting data from the storage by the server as and when required. However, an important point to note here is that in case of SAN, multiple servers can access the same storage at the same time. 2. Server to server (Tate) - This type of transfer facilitates communication between servers 3. Storage to storage (Tate) - A storage device can automatically be used to request data from the backup without involving the server to monitor the routine tasks, or in case of disaster recovery. SAN effectively facilitates data transfers between the storage utilities and the servers requesting data without restricting it to a specific distance in which it can be managed. SAN is a highly evolved concept working on the basic principles of networked storage: a dedicated storage network that manages data requests from the servers using high-speed transfers that can span larger distances using Fiber Channel1 over IP (FCIP) architecture, an arrangement that allows for a greater amount of redundancy, in an attempt to deliver high performance and increased "local" availability. [Figure 2 - Storage Area Networks] (allSAN.com) An important point to note here is that SAN provides for high-speed, long distance transfers through its use of Fiber Channel switches, acting as points of connection between devices placed at a distance. However, due to its switched nature, is able to provide a dedicated path between devices to make full utilization of the bandwidth in the duration of the communication. Because of its' channel like facilities, this FC infrastructure provides all applications with the view as though all storage is locally attached. Fiber Channel is able to support multiple protocols (Tate) and a diverse range of devices, which are easily manageable as a network. Impacts on Business / Industry Organizations whose operations are largely dependent on data management and storage, requiring a centrally pooled storage solution contemplate over the usefulness of SAN in supporting their business operations as well as carry out cost benefit analysis to justify the value of their investment for such a solution. The answer to this question depends largely on a needs-analysis carried out to determine the current storage strategy and the adoption of a newer one to suit the future business needs of the company. Although if required by any company to centralize or streamline its data storage capabilities, SAN may be the best solution, however there is only one barrier that acts as an obstacle: cost. The prices may be dropping these days however SANs will most likely dominate the big businesses, to remain at levels outside the reach of SMEs. Once the prices fall to a considerable level, I suggest it would still not before a considerable amount of time that organizations will take to understand that data management by SAN is facilitated through the most basic functions of network storage. It is to be understood that behind these acronyms lies a technology stack that has been developed to provide the most easiest and comfortable means of offering the oldest of network services, that of data availability on client machines. In terms of benefits, SAN provides the following over other storage competitors: 1. SAN provides a simplified shared storage model that eases the task of administration as well as providing a flexible storage solution that eliminates the need of relocation when moving devices from one location to the other 2. SANs facilitate disaster recovery in a remarkable fashion. It provides for easy storage replication through server storage and data management utilities, or by SAN's own specialized software applications. SANs can span long distances using secondary storage arrays, with support from specially developed protocols to ensure business continuity, such as Fiber Channel over IP and iSCSI protocols, comparable to traditional SCSI layers taking much longer with distance spanning only a few meters. 3. SAN facilitates increased disk utilization by providing improved storage asset utilization mechanism. Comparatively, the adoption of SAN improves the average utilization rates (between 60 to 90 percent) 4. Implementation of a SAN solution can reduce requirements for additional staff in comparison to staff needed to support server-attached, distributed storage. 5. Server-less backup, copying data from a storage device a backup device directly without server intervention, using high-speed FCIP channels of SAN. Driving Forces behind SAN in IT Markets Following are some of the forces that have a huge impact on companies looking for alternative solutions for network storage that provide them with all-time/anywhere facility to access information: 1. Capacity for efficient backups - In an era of increased storage requirements and 24/7/365 availability, this produces a large overhead on networks working with traditional protocols 2. Growth in storage capacity requirements 3. Flexibility and cost-effectiveness - The movement of information in a SAN storage network means that the servers may no longer require configuration of the native storage device. With its own dedicated connection and bandwidth, the SAN network storage capability allows server-free movement of data, thereby reducing server cycles (Tate) for tasks such as backup, recovery, archiving or recalling. This results in significant cost savings against the installation and subsequent configuration of a SAN-enabled network storage facility. 4. Availability and performance 5. "Best of Breed" (Tate) - Since the decision to select a network storage solution in case of SAN eliminates the need to be dependent on the server's configuration, this allows buyers to select a solution based on performance, functions, cost and other factors. 6. Scalability - With growing information management requirements, this has become increasingly challenging to adapt to the changing needs without planning for a huge costs based on infrastructure requirements as well as the changing network storage solutions. SAN, on the other hand, allows flexible disk storage capabilities, enhanced independently of the servers handling the flow of information. Works Cited allSAN.com. Storage Area Networks. 2000. 21 April 2009 . Bird, Drew. Storage Basics: Storage Area Network. 26 February 2002. 21 April 2009 . Info Advantage. Storage Area Networks. 2009. 22 April 2009 . Tate, John, Cole, Geoff, Gomilsek, Ivo. Designing an IBM Storage Area Network. San Jose: International Business Machines, 2000. Troppens, Ulf, Erkens, Rainer, & Muller, Wolfgang. Storage Networks Explained. John Wiley and Sons, 2004. Read More