What is the origin of a fiber switch?
In the past we see the data storage is basically in the server directly connected to several SCSI, IDE and the like disk, which is what we often hear DAS (direct connection storage) way. This point-to-point disk system is clearly difficult to expand and storage performance is difficult to improve the lack of. Not only that, by the IDE and SCSI interface physical performance constraints, and its connection to the disk is usually only up to 20 meters within the connection distance, greatly limiting the disk storage system expansion.
In order to solve these deficiencies in the above DAS storage methods, network equipment manufacturers and standards development experts began to consider the development of a new storage technology, a fundamental solution to DAS storage mode transmission rate and connection distance. At first people think of a storage system is independent, as a network device on the network node, which can greatly reduce the server's data storage load, but also greatly expand the disk storage system, which is the later NAS (network Additional storage) mode.
This storage is indeed a considerable extent to solve the previous DAS storage deficiencies, to meet the vast majority of small and medium enterprises to local storage needs. And it is the biggest feature is simple, with the same IP protocol with the Ethernet, network administrators can easily grasp the deployment of NAS storage systems, by many enterprises are widely welcomed. But NAS is still not fundamentally solve the problem of disk storage performance and connection distance, in general, disk storage performance has not been fundamentally improved, but to improve the network export bandwidth.
It is because the NAS is still the above shortcomings, so people continue to develop a new way of network storage, that is, SAN storage. The biggest feature of this storage is the Fiber Channel (Fiber Channel) protocol, which provides Gigabit serial network access for storage devices, and then build Fiber Channel-based, Fiber Channel, The SCSI protocol used for storage, the IP protocol for the network, and the virtual interface (VI) protocol mapped to the network architecture, so that various types of network devices and channels can be supported. The Fiber Channel protocol combines a number of advantages, such as a network-wide maximum distance of up to 10 kilometers, a simple serial cable that can use multiple media, a gigabit network rate, and a variety of protocols that can be used simultaneously on the same cable.
A SAN is a network of storage devices and system components. All communications are done on a Fiber Channel network and can be used to centralize and share storage resources instead of NAS storage as a network node Of the network equipment. SAN not only provides high-performance connectivity to data devices, improves data backup speed, and adds redundant connectivity to storage systems, providing support for highly available cluster systems. Simply put, SAN is a dedicated Fiber Channel network (different from Ethernet) that connects storage devices and servers, but it has a similar architecture to Ethernet, as well as servers that support Fiber Channel, Fiber Channel cards (Fiber Channel), Fiber Channel Hub / switch and Fiber Channel storage devices. Technically speaking, the three most important components of SAN networks are: device interfaces (such as SCSI, Fiber Channel, ESCON, etc.), connecting devices (switches, gateways, routers, hubs, etc.) and communication control protocols such as IP and SCSI Wait). These three components, together with additional storage devices and servers, form a SAN system.