Storage Area Network (SAN) is a high-speed subnetwork of shared storage devices. A storage device is a machine that contains nothing but a disk or disks for storing data.
A SAN's architecture works in a way that makes all storage devices available to all servers on a LAN or WAN. As more storage devices are added to a SAN, they too will be accessible from any server in the larger network. In this case, the server merely acts as a pathway between the end user and the stored data
From Enterprise Storage Forum: A SAN is a network of storage devices that are connected to each other and to a server...in some configurations a SAN is also connected to the network. ... it is forecast to become the data storage technology of choice in the coming years.
SANs originated to overcome the problems with network attached storage (NAS) devices, which - like ordinary servers - are difficult to manage and difficult to expand the capacity on. NAS devices also add to the traffic on the network and suffer from the delays introduced by the operating systems' network stacks.
A SAN is made up of a number of fabric switches connected in a network. The most common form of SAN uses the Fibre Channel fabric protocol (with Fibre Channel switches). Alternatively ISCSI could be used with IP switches.
Connected to the SAN will be one or more Disk array controllers and one or more servers. The SAN allows the storage space on the hard disks in the Disk array controllers to be shared amongst the servers.
A SAN is a dedicated network that is separate from LANs and WANs. It is generally used to connect all the storage resources connected to various servers. It consists of a collection of SAN Hardware and SAN software; the hardware typically has high inter-connection rates between the various storage devices and the software manages, monitors and configures the SAN.
Introduction
The main objective of a SAN is to facilitate the exchange of data between operating systems and storage elements. Components of a SAN infrastructure include communication infrastructure, storage elements, computer systems, and a management layer. The connecting elements of a SAN network include routers, gateways, hubs, switches and directors. A SAN removes restrictions on the number of servers that a storage utility can be attached to. The flexible networking of a SAN eliminates the need for physical proximity between the server and the storage devices. Benefits of a SAN include faster transfer of data to the intended destination with minimum utilization of server capacities, access for multiple hosts to several storage devices, independent storage speeds up applications and offers better availability, the management of stored data is easier and centralized and devices are more amenable to scalability.
SANs have led to the development of several new methods for attaching servers to storage devices such as optical jukeboxes, tape libraries, and disk arrays.
The high-speed transfer of data via a SAN can occur in the following ways –
1. Connecting server/s to storage devices – This is the most commonly used method and allows for the access of a storage device by servers either serially or simultaneously.
2. Connection between servers – SAN enables high-volume transfer of data between servers.
3. Connection between storage devices – Useful for moving data between storage devices without eating into server capacities which can then be utilized for other activities.
The need for SAN
The I/O bandwidth of the networks that were earlier used to connect the data storage devices and the processors was not commensurate with the capacities of the disk arrays and computers that utilized the data stored in them. The access to data is further complicated by the different database software run on different platforms. Managing different file systems and data formats requires trained manpower. The traditionally distributed storage has been a huge drain on management resources and inefficient as well in terms of capacity utilization of hardware resources. Scalability is also an issue when disk capacity is tied down to a single server or client. Sharing of data often requires creating duplicate copies, moving these copies slows down the LAN/WAN and often co-ordination between applications such as BI, CRM, and ERP that are spread over the entire organization becomes very difficult.
SAN infrastructure
SAN topologies are predominantly developed using fiber channels. Fiber channel is an open technical standard developed for networking and is especially useful for handling storage communications as it offers flexible connectivity and fast access to data. Optical fibers are used for long-distance networking and copper cable links are preferred for shorter distances due to their lower cost. Fiber channels can support different protocols and a large number of devices, a quality very desirable in any networking solution.
The American National Standards Institute (ANSI) has laid down the standards on which fiber channel networks are based. These standards define the manner in which data is to be moved across networks. The standards are exhaustive and cover physical interfaces, data encoding practices and protocols, data delivery methodologies, and common services. Fiber channels offer the advantage of a high level of hardware processing to ensure high performance. The serial data transport scheme used in a fiber channel can be implemented using simple cables and connectors. The information can be routed easily through switched networks. Since fiber channel transport layers are protocol independent, they enable the transmission of multiple protocols. Apart from being extremely flexible in its application, fiber channel delivers data at the rate at which the receiving application is able to handle; besides there is no loss of data.
Storage
Storage devices commonly connected through SAN include disk systems and tape systems. Disk systems offer simple integration as the I/O control is centralized. Disk systems are classified as Just A Bunch Of Disks (JBOD) and Redundant Array of Independent Disks (RAID). Disks in a JBOD are treated as individual storage devices by the applications they are connected to. RAIDs are treated as a single device that has a higher fault tolerance. An array of disks can be made to behave as a JBOD or RAID depending upon the performance requirements of a SAN. Disk systems are preferred for online data storage because of their high performance.
Tape systems make use of tapes arranged serially; parallel arrangements are not possible. Tape systems consist of drives, autoloaders, and libraries. Tape drives connect the tapes to the devices and enable the reading/writing from and to the tapes. Tape autoloaders are tape drives that perform the function of auto backup; they are used for devices that generate a lot of data constantly. Tape libraries are autonomous sets of tape drives and autoloaders. They are used in situations where the storage capacity required is very high. Tape systems are used for offline storage because of their cost efficiency.
Benefits of SAN
One of the chief benefits of SAN is that it simplifies the network infrastructure and makes it easier to manage. This it does by means of consolidation, virtualization, automation, and integration. Consolidation aims at centralizing the storage to improve scalability, reducing infrastructure complexity, and increasing efficiency. Virtualization helps improve availability and reduces costs as it offers a holistic view of storage components. Automation of routine tasks allows the administrators to focus on critical tasks. Automation also improves responsiveness. Integration helps organization furnish users with the desired information in a more systematic manner.
A SAN makes information lifecycle management easier because of the integrated view of the data that it offers.
Perhaps the biggest benefit of a SAN is that it complements expensive business applications that demand instant and real-time information. ERP and CRM systems can fulfill their business promise only if the right type of data is made available at the right time to the right person. To this end, a SAN is most useful and appropriate.
A SAN's architecture works in a way that makes all storage devices available to all servers on a LAN or WAN. As more storage devices are added to a SAN, they too will be accessible from any server in the larger network. In this case, the server merely acts as a pathway between the end user and the stored data
From Enterprise Storage Forum: A SAN is a network of storage devices that are connected to each other and to a server...in some configurations a SAN is also connected to the network. ... it is forecast to become the data storage technology of choice in the coming years.
SANs originated to overcome the problems with network attached storage (NAS) devices, which - like ordinary servers - are difficult to manage and difficult to expand the capacity on. NAS devices also add to the traffic on the network and suffer from the delays introduced by the operating systems' network stacks.
A SAN is made up of a number of fabric switches connected in a network. The most common form of SAN uses the Fibre Channel fabric protocol (with Fibre Channel switches). Alternatively ISCSI could be used with IP switches.
Connected to the SAN will be one or more Disk array controllers and one or more servers. The SAN allows the storage space on the hard disks in the Disk array controllers to be shared amongst the servers.
A SAN is a dedicated network that is separate from LANs and WANs. It is generally used to connect all the storage resources connected to various servers. It consists of a collection of SAN Hardware and SAN software; the hardware typically has high inter-connection rates between the various storage devices and the software manages, monitors and configures the SAN.
Introduction
The main objective of a SAN is to facilitate the exchange of data between operating systems and storage elements. Components of a SAN infrastructure include communication infrastructure, storage elements, computer systems, and a management layer. The connecting elements of a SAN network include routers, gateways, hubs, switches and directors. A SAN removes restrictions on the number of servers that a storage utility can be attached to. The flexible networking of a SAN eliminates the need for physical proximity between the server and the storage devices. Benefits of a SAN include faster transfer of data to the intended destination with minimum utilization of server capacities, access for multiple hosts to several storage devices, independent storage speeds up applications and offers better availability, the management of stored data is easier and centralized and devices are more amenable to scalability.
SANs have led to the development of several new methods for attaching servers to storage devices such as optical jukeboxes, tape libraries, and disk arrays.
The high-speed transfer of data via a SAN can occur in the following ways –
1. Connecting server/s to storage devices – This is the most commonly used method and allows for the access of a storage device by servers either serially or simultaneously.
2. Connection between servers – SAN enables high-volume transfer of data between servers.
3. Connection between storage devices – Useful for moving data between storage devices without eating into server capacities which can then be utilized for other activities.
The need for SAN
The I/O bandwidth of the networks that were earlier used to connect the data storage devices and the processors was not commensurate with the capacities of the disk arrays and computers that utilized the data stored in them. The access to data is further complicated by the different database software run on different platforms. Managing different file systems and data formats requires trained manpower. The traditionally distributed storage has been a huge drain on management resources and inefficient as well in terms of capacity utilization of hardware resources. Scalability is also an issue when disk capacity is tied down to a single server or client. Sharing of data often requires creating duplicate copies, moving these copies slows down the LAN/WAN and often co-ordination between applications such as BI, CRM, and ERP that are spread over the entire organization becomes very difficult.
SAN infrastructure
SAN topologies are predominantly developed using fiber channels. Fiber channel is an open technical standard developed for networking and is especially useful for handling storage communications as it offers flexible connectivity and fast access to data. Optical fibers are used for long-distance networking and copper cable links are preferred for shorter distances due to their lower cost. Fiber channels can support different protocols and a large number of devices, a quality very desirable in any networking solution.
The American National Standards Institute (ANSI) has laid down the standards on which fiber channel networks are based. These standards define the manner in which data is to be moved across networks. The standards are exhaustive and cover physical interfaces, data encoding practices and protocols, data delivery methodologies, and common services. Fiber channels offer the advantage of a high level of hardware processing to ensure high performance. The serial data transport scheme used in a fiber channel can be implemented using simple cables and connectors. The information can be routed easily through switched networks. Since fiber channel transport layers are protocol independent, they enable the transmission of multiple protocols. Apart from being extremely flexible in its application, fiber channel delivers data at the rate at which the receiving application is able to handle; besides there is no loss of data.
Storage
Storage devices commonly connected through SAN include disk systems and tape systems. Disk systems offer simple integration as the I/O control is centralized. Disk systems are classified as Just A Bunch Of Disks (JBOD) and Redundant Array of Independent Disks (RAID). Disks in a JBOD are treated as individual storage devices by the applications they are connected to. RAIDs are treated as a single device that has a higher fault tolerance. An array of disks can be made to behave as a JBOD or RAID depending upon the performance requirements of a SAN. Disk systems are preferred for online data storage because of their high performance.
Tape systems make use of tapes arranged serially; parallel arrangements are not possible. Tape systems consist of drives, autoloaders, and libraries. Tape drives connect the tapes to the devices and enable the reading/writing from and to the tapes. Tape autoloaders are tape drives that perform the function of auto backup; they are used for devices that generate a lot of data constantly. Tape libraries are autonomous sets of tape drives and autoloaders. They are used in situations where the storage capacity required is very high. Tape systems are used for offline storage because of their cost efficiency.
Benefits of SAN
One of the chief benefits of SAN is that it simplifies the network infrastructure and makes it easier to manage. This it does by means of consolidation, virtualization, automation, and integration. Consolidation aims at centralizing the storage to improve scalability, reducing infrastructure complexity, and increasing efficiency. Virtualization helps improve availability and reduces costs as it offers a holistic view of storage components. Automation of routine tasks allows the administrators to focus on critical tasks. Automation also improves responsiveness. Integration helps organization furnish users with the desired information in a more systematic manner.
A SAN makes information lifecycle management easier because of the integrated view of the data that it offers.
Perhaps the biggest benefit of a SAN is that it complements expensive business applications that demand instant and real-time information. ERP and CRM systems can fulfill their business promise only if the right type of data is made available at the right time to the right person. To this end, a SAN is most useful and appropriate.