Summary 1)What is SAN 2)Basics of SAN 3)Architecture of SAN 4)Basic mechanism of SAN
What is SAN Storage area network is a design to transfer data, from server to clients. It is alternative to the directly attached targets. It is primarily used as the storage device server can access this. It is also highly performance storage device enabling to communicate with one another.
technologies • Different of technologies are used for SAN. Most popular is the Fiber channel. But IP based solutions are also used. Concepts of SAN also implemented on the devices those are attached to like disk, tapes, RAID, file server etc. We frequently used NAS and SAN collaterally. Difference between them are SAN is network storage sub system NAS is storage subsystem. SAN extension of disk channel not connected to server but NAS connected to server via IP network.
Basics of san • Different technologies can be used to interconnect different network nodes. Fiber channel is dedicated high performance channel. It is used fiber channel protocol. SCSI protocol carry IP packet over the network. SCSI is the extension of the SCSI bus.
Initiator and target • Fiber channel can be source or the destination of the information. If the node is initiator then it is connected to the network through HBA (Host Bus Adapter) it is a physical layer connection. It may be electrical or fiber optical. If the node is target then it is connected through RAID (Redundant Array of Independent Disk) or storage drives.
Hard drives • Basic storage is the hard drives. It is composed of different disks, platters, cylinders, track and sectors. It is metallic disk used for storage of data. Logical block address within the disk is 512 byte. Files can be stored in the sectors so they can be stored and retrieved. File system deals with clusters of blocks and it uses FAT (File Allocation Table) to map the file sectors.
Jbod and raid • Jbods are group of disks packaged in a connected via FC loop. RAID is more sophisticated device it improves the storage disk performance. It improves the performance the reading and writing from disk at the same time or it mirroring the information on the multiple disk array.
Architecture of san • RAID array containing the disk array and RAID controller . It providing hardware and feature of RAID 0- 5. Direct attached storage is an architecture is used to storage privately attached servers. It is expensive and complex to manage. Storage is accessed from block level not file level. It is high performance. It uses good management tool and storage is shared. It uses interoperability.
nas • Network attached storage is an architecture which attached to the server with a multiprocess network. This network is a IP process network. Transmission Control Protocol can be tuned to optimized storage transport.
Mechanism of san • Fiber channel act as a transport layer of SCSI. Fiber channel is used instead of TCP/IP network to connect server to the storage. In the long graphical distance IP can be used. It can be used in the IP traffic. FC offers layer 2 transport service and used layer 3 to map upper layer protocols like SCSI, HIPPI and IP.
Switching fabric service • FC switching fabric relies upon number of software applications and to deliver transport service. • Most relevant ones are Zoning, Alias service, domain controller. • Those service allow fabric to function without disruption. • It consist of a set of information distributed across the fabric nodes.
Standardization body • Fiber channel standardized by ANSI T11 committee. • SCSI standardized by T10 committee. URL = www.T10.org • FCIA is the fiber channel industry association it is not involved in the standardization process. University of New Hampshire also involved here.