Storage Area Network (SAN) is that network which provides accessibility to block level consolidated data storage. The SANs are used primarily for enhancing storage devices like optical jukeboxes, disk arrays and tape libraries. SAN has server accessibility such that device appears to operating systems like attached devices locally. Typically SAN has own storage device networks which is not accessible generally by means of (LAN) local area network by different devices. Complexities and costs of SANs had dropped in 2000s year early to levels. It allowed wide adoption through small and enterprise to medium-sized environments of business. SANs do not provide file abstractions. It provides only block levelled operations. But, file systems created on top of the SANs provides file levelled accessibility. It is called shared-disk file systems.
Infrastructure of SAN: The SANs use often topology of Fibre Channel Fabric. It is infrastructure which is designed especially for handling storage communications. This provides fast and most reliable accessibility than high levelled protocols that are used in NAS. It is fabric being same in concepts to network segments in local area networks. Fibre Channel SAN fabric typically is created of number of switches of Fibre Channel. Presently, all important vendors of SAN equipment offer few forms of routing solutions of Fibre Channel. These bring scalability benefits substantially to architecture of SAN. This allows data crossing in between various fabrics with no merging them. Offerings thereby use protocol proprietary elements and top levelled architectures that are promoted as being different radically. There is enabling of mapping Fibre Channel traffics over IP or over SDH/SONET.
SAN Storage QoS (Quality of Service): SAN Storage QoS (Quality of Service) is performance and capacity coordination in storage area network dedicated. It enables storage desired performance being maintained and calculated for customers of network that access device. Important factors affecting SAN Storage QoS (Quality of Service) are: Latency: It is delay of time for operation execution of writing and reading. Queue depth: It is numbers of operations outstanding that wait for execution to disks that are underlying (SSD or traditional). Bandwidth: It is data throughput rate present on system. QoS is impacted in storage system of SAN by increase unexpectedly in data traffics (usage spikes).
It is from 1 network user which causes decrease in performance for different users on similar network. This is called “Noisy Neighbour Effect”. When services of QoS are enabled in storage system of SAN then “Noisy Neighbour Effect” is prevented. Storage performance of network is predicted correctly.