Storage Area Network (SAN)

As its name suggests, a storage area network (SAN) is a kind of network that functions as a connection from the hard drive system to the server networks. With SANs, the entire storage capacity, i.e. storage devices like HDDs, SSDs, disk arrays, and tape libraries, are compiled into a virtual storage unit that can be centrally managed. Servers configured in compliance with this structure provide the basis for accessing SANs. The storage network operates alongside the local area network (LAN) and provides it with the entire bulk memory. A SAN can therefore be seen as a sort of a secondary network intended exclusively for transferring data for storage purposes.

SANs also needn’t be located in the same place as the server in order to function. Furthermore, they operate independently of the operating system of the computer being accessed; this makes them particularly ideal for cross-platform options. SANs were developed with the intention of helping to tackle the management problems that dedicated hard drive servers are often responsible for. Through its shared virtual storage space, storage area networks provide noticeably more effective and flexible solutions for dealing with large volumes of data. In contrast to simple network storage solutions like network attached storage (NAS), SANs prevent LANs from being overburdened.

Due to its complicated system architecture, which in part requires very expensive hardware, setting up a storage area network can prove to be a complicated and cost-intensive undertaking. Excluding the cables and other basics, the following fundamentals are needed for setting up a SAN server:

• Fiber channel fabric: in the IT world, the term ‘fabric’ encompasses a network of cable lines and switches that boast a high redundancy due to their multiple cross connections. In addition to enabling an enormous data throughput, this set-up also provides a high bandwidth as well as increased reliability. Fabric composed of fiber channel switches and fiber optic cables make up the core of storage area networks. In doing so, all devices using SANs are linked to the fiber channel switch, thereby providing the necessary connections needed for data access to be carried out in real time between senders and recipients. As standard interfaces for storage networks, fiber channels are designed to provide a steady high-speed data transfer, measuring up to 16 Gbit/s.

• Storage elements: disk arrays are generally the go-to storage devices used for SANs. This is where devices with multiple hard disk drives (HDDs or SSDs) intended for mass storage purposes come into play. In order to ensure that stored data is easily accessed, modern disk arrays possess controllers; this provides both redundant data storage and load distribution for data transfer. This makes data more secure and additionally increases transfer rates. Implementing a redundant storage process is normally carried out using a RAID system (redundant array of independent disk) that aggregates the individual, physical hard drives of disk array into a logical disk drive. Alternatively, tape libraries, or single hard drives can be imported into a SAN.

• SAN servers: SANs require specially configured servers in order to optimally control data access. This enables the network to serve as a link between the storage network and terminal devices connected to the LAN. For this purpose, special hardware interfaces (host bus adapters, or HBAs) are connected to the fiber channel switch.

A storage area network is specifically set up to provide high availability. Despite potential breakdowns of individual hardware components, the ability of this computer system makes it possible to deliver hitch-free business applications.

Redundant storage cycles

If SAN storage is powered by disk arrays, then the required redundancy for virtual storage units is generally provided through RAID implementations. This is due to the fact that data found in full-fledged RAID systems is generally mirrored in two different physical storage devices. Moreover, increasing availability and reducing the risk of crashes for storage units can be accomplished by implementing two RAID controllers. Disaster scenarios can also be avoided by storing identical datasets in two different locations. Setting up a redundant storage network also involves incorporating a proper supply engineering into your set-up. Companies should therefore ensure that their power supply adapters are equipped with backup ventilator and cooling elements.

Those operating SANs profit from the combined capacities of varying data storage. The ability on the part of a storage area network to aggregate various physical data storage capacities into a solid storage foundation is a particularly attractive feature for server operators. This option provides users with servers that are both platform independent and flexible. Decoupling storage devices from accessed servers enables storage capacity to be easily managed and scaled as needed; excessive burden is also removed from the LAN. Storage area networks based on fiber optic technology support high data transfer rates due to their fiber channel’s standard interface.

Multipathing and cross connections based on fiber channel fabric prevent overloading and ensure constant availability of data stored in SANs. Access between data pools and users can occur through multiple routes. Redundantly distributing data onto multiple physical systems guarantees the high security of saved data. Delays when simultaneously accessing data is furthermore reduced. Due to its effective storage management, SAN is often used as a platform for virtual servers; this is offered to customers as a cloud-based IaaS (infrastructure as a service).