Advantages of Network Attached Storage

SAN storage and host connectivity is generally configured with no single point of failure (NSPOF). This is not a requirement, just a good business practice. NSPOF is accomplished at several levels throughout the architecture. Examples are dual-everything (controllers, power supplies, fans, switches, etc.), including dual physical paths to redundant PCI interfaces in the host computers. Path and single device failures in the SAN are usually transparent to the operating system and applications.
Technically (mathematically/scientifically), the on-disk implementation of the RAID technology is more robust resulting in an even lower probability of data loss over conventional PCI or integrated RAID controllers.
Increased storage requirements can be implemented without the purchase of physically larger servers which accommodate greater quantities of direct-attached disks and/or without the purchase of additional servers simply to provide more storage. A side advantage here is the ability to consume less rack space by using small 1-2U servers which are SAN attached.
SAN storage is high performance, high I/O bandwidth, due to the 2-4Gbps Fibre Channel interconnect, simultaneous use of multiple 2-4Gbps paths, striping of disk spindles in the storage subsystem and concurrent utilization of redundant storage controllers.
Because storage expansion is so easy in a SAN environment, SAN storage subsystems allow customers to successfully manage their actual used storage as a greater percentage of total available storage. When storage requirements increase, disks may simply be added to the subsystem. It is common to also be able to non-intrusively add disk shelves, intelligent controllers and additional subsystems as well.
A large real cost of storage is the human component, i.e., labor, to manage it. Industry norms are that in a SAN environment, a given storage manager/system administrator can manage between six and ten times the amount of SAN storage as compared to direct attached storage.
SAN storage subsystems provide access to multiple servers with multiple operating systems thus providing the advantage of centralized storage, management and flexibility.
Storage subsystem technology provides enhanced capabilities such as logical drive snapshotting and cloning. This is further complimented by the ability for multiple servers to concurrently share a tape library over the SAN. These technologies can result in significantly reduced backup windows.
Fibre Channel (FC) technology allows for the option of physical space diversity for servers, storage and tape libraries. This is due to the 100-500m distance specification for FC over multi-mode fiber. Greater distances are possible with single-mode fiber and additional equipment.
Due to web management GUIs, SANs can be managed from any authorized, web-enabled client system on the network.