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What is a storage area network?

What is a storage area network?

Whether it’s the hard disk spinning in your laptop or the rows of humming drives in a data centre, data storage is a critical part of computing. Computers and servers access stored data using a range of methods and technologies, from the relatively simple to the highly complex.

Storage area networks (SANs) are at the forefront of storage technology. But what is a SAN? How do SANs work? And what are the benefits of using one to store and access your data?

A dedicated, high-performance storage network

In essence, a storage area network takes a large quantity of storage devices, and compiles them into a single unit of storage capacity that can be managed centrally.

A network of computers and servers connects to the SAN to access data storage. This differs from traditional direct-attached storage (DAS), where a server simply has its own storage drive directly attached to the hardware. When a server uses SAN, by contrast, it can access storage as if it was directly attached, without needing to be in the same physical location.

But the SAN isn’t just part of an existing network of machines; it forms an independent network exclusively for data storage. For this reason, a SAN is a very sophisticated setup. As well as the storage hardware, it demands high-end, specialised cabling and switches to ensure top levels of data throughput.

SAN vs NAS

It’s helpful to compare SAN to other solutions for data storage on a computer network. Network-attached storage or NAS is similar to SAN in that it provides storage for a network of machines. But unlike SAN, NAS takes the form of a storage device, directly plugged into a network switch – essentially just another computer or server sharing the network.

A fundamental architectural difference between SAN and NAS is that SAN provides block-level storage, and NAS provides file-level storage. In practice this means that a server’s operating system sees a storage area network as a drive, while network-attached storage is treated as a file server, i.e. data is presented as individual files and folders, and is retrieved via the client-server communication model.

NAS is far less complex and a lot cheaper than SAN, with much lower requirements in terms of hardware and cabling. This makes it a popular choice for less data-intensive use cases such as home offices or onsite storage for small businesses. However, SAN can offer considerably higher levels of scalability, performance and reliability.

Why choose SAN for your data storage?

First and foremost, a SAN is highly scalable. Storage devices aren’t coupled to the servers or computers accessing them, so capacity can be added to a central pool as the need arises.

A SAN implements multiple data paths, meaning data can be accessed through different routes on the network. This increases the availability of data, since access isn’t dependent on a single path. A SAN can also provide exceptional reliability, with data distributed across multiple nodes to ensure it remains available, even if a storage drive fails. And a SAN is a high-speed network, so it can easily provide the fast access times demanded by database-intensive applications like ecommerce.

Another advantage of SAN is platform independence. Because a SAN operates independently from the OS of each server, it can provide storage in a cross-platform network. From the point of view of both Linux and Windows machines, the SAN is a normal storage drive.

SAN and virtualisation: an ideal combination

The scalability and flexibility of SAN makes it a perfect match for virtualised services. Large deployments of virtual machines (VMs) often run with a diverse range of operating systems and applications, but a platform-independent SAN can provide for all their storage needs, while also delivering outstanding availability.

At Fasthosts, our CloudNX platform offers high-performance SAN storage for Virtual Private Servers. Our SAN only uses solid-state drives (SSDs), offering significantly faster access times than traditional hard disks. Availability is also ensured, with data stored across a network of nodes for maximum reliability, even in the event of hardware failure. Get in touch online or by phone for more details on our secure and reliable cloud hosting services.

Neal Thoms's picture

Neal Thoms

Author As a content creator for Fasthosts, Neal’s main focus is cloud technology and how it’s transforming everything we do online. He’s worked in the web hosting industry for over five years.