Storage Area Networks

Storage Area Networks

The Storage Area Networks  Industry Association (SNIA) defines a storage area network (SAN) as a network whose main purpose is the transfer of data between computer systems and storage elements. A SAN consists of a communication infrastructure, which provides a physical connection. 

It also includes a management layer, which regulates connections, storage elements, and computer systems so that data transfers are safe and strong. The term SAN is usually (but not necessarily) identified with block I O services rather than file service access. Simply put, SAN is a special high-speed network that connects servers and storage devices. 

SANs are sometimes referred to as networks behind servers. SANs allow any connection to the entire network, using interconnection elements, such as switches and directors. SANs eliminate traditional special connections between server and storage, and the concept that the server effectively owns and manages device storage. 

SAN also removes any restrictions on the amount of data that can be accessed by the server. Traditionally, servers are limited by the number of storage devices attached to individual servers. In contrast, SANs introduce network flexibility to enable one server or many heterogeneous servers to share common storage utilities. 

Devices Across Storage Area Networks 

The network may include many storage devices, including disks, tape, and optical storage. In addition, the storage utility may be far from the server it uses. SAN can be seen as an extension of the storage bus concept. This concept allows storage devices and servers to be interconnected by using similar elements, such as LANs and wide area networks (WANs). 

The diagram in Figure 1-10 shows an overview of SANs that connect multiple servers to multiple storage systems. SAN makes a new method for attaching storage to the server. This new method can be activated by a large increase in availability and performance. 

SANs are now accustomed to connecting shared storage arrays and tape libraries to multiple servers, and they are used by clustered servers for failover. SAN facilitates direct, data transfer high-speed between servers and storage devices, potentially in one follows three ways: Server to storage: This method is a traditional interaction model with storage devices. 

The advantage is that the same storage device can be accessed serially or simultaneously by several servers. Server to server: SAN can be used for high-speed and high-speed communication between servers. Storage to storage: This ability to move paste data allows data to be moved without interference from the server, therefore freeing up the server processor cycle for other activities, such as application processing in Storage Area Networks . 

Examples include disk devices that back up data to tape devices without server intervention, or remote mirroring devices across SANs. SANs can allow applications that contain data for better performance, by sending data directly from the device to the target device with minimal server intervention. 

Without also allowing a new network architecture where many hosts access multiple storage devices connected to the same network. The use of SANs has the potential to offer the following benefits: Increased application availability: Storage does not depend on applications and can be accessed through several data lines for better reliability, availability and ease of service. 

Higher application performance: The storage process is lowered from the server and transferred to a separate network. Transfer and jump data to remote locations: A copy of remote data is activated for disaster protection and against malicious attacks. Simple centralized management: One image from storage media simplifies management, Storage area networks is a high-speed network for you.