Storage Area Network

Understanding The Basics Of SAN Technology

In today’s competitive business environment, virtually every industry and technology focus area is under intense pressure to deliver more performance at a lower cost and the storage technology world is no exception to this. For the SAN market, in particular, much of the focus is not only on reducing the overall cost of the systems but also in making more optimal use of disk space and reducing power and energy requirements of SAN systems. Optimal storage space utilization is being pursued on a number of fronts, beginning with an emphasis on reducing (or eliminating) duplicate data on a storage infrastructure, a process known as deduplication. Deduplication is the process of eliminating duplicate files or data blocks across storage volumes. Typically, deduplication approaches can be defined as either “inline” or “post-process”. An inline deduplication implementation identifies and eliminates duplicate data as it is moved between host and target. A post-process implementation works after the data has been initially written to disk by identifying and eliminating duplicate data after the initial write. Deduplication approaches offer to reduce duplicated data in the range of 50-95% so you can see that some significant cost savings can be achieved over time. Until recently, deduplication has been a feature offered solely by disk backup and virtual tape library (VTL) tools but vendors are beginning to add deduplication feature sets into their network-attached storage (NAS) systems as well. Sophisticated storage management and reporting tools are also being actively used to monitor and report on utilization of the storage infrastructure and to highlight opportunities for improvement.



Another area of emphasis in the quest to reduce costs and improve the overall return on investment for SANs is the energy footprint of the storage infrastructure and the associated server space required by these systems. The overall energy footprint is being aided (i.e. total energy consumption is being reduced) through core technology improvements in the actual power consumption of storage systems. In addition, larger disk drives have resulted in improved storage density which leads to an improved optimization of server floor space used. Because an increase in server floor space indirectly equates to increased cooling and power costs, reducing floor space required by the storage infrastructure can have a direct impact on the hosting expenses. Drive manufacturers are also aggressively implementing spin-down technologies that cause drives to stop moving when not being used while still being able to rapidly spin up – offering excellent performance at a lower total amount of power consumed. The most optimal “spin-down” drives are the solid state drives (SSDs) which obviously don’t spin at all. SSDs currently compete very effectively in the area of performance and power consumption but are still more expensive than their mechanical drive counterparts.

An additional item that is driving both the adoption of SANs but also the improved cost-efficiency of these systems is the uptake of SANs in the small-to-medium-sized business (SMB) environment. Shared storage environments such as SANs, when combined with virtualized servers and the ability to share storage capacity across these multiple hosts allows smaller businesses to more effectively scale up infrastructure as required, while retaining the benefits offered by SANs for companies that are much larger.

Another trend related to SANs is the increasing popularity and adoption of iSCSI and related multi-protocol storage technologies. iSCSI is increasingly becoming a popular option for businesses that realize that their current needs would only utilize a fraction of available fiber-channel capacity, making iSCSI a more practical and more cost-effective solution that better meets their needs. The rapid acquisition of many of the smaller iSCSI specialty companies by the larger storage infrastructure companies mean that the power of iSCSI is rapidly being combined with the more sophisticated management tools offered by the larger companies. Multiprotocol storage options go beyond iSCSI to include additional multiple protocols such as NFS, CIFS, and fiber channel. A multiprotocol storage solution consolidates SAN and NAS arrays into a finite number of multiprotocol arrays which helps simplify the management and configuration of these disparate environments.