The difference between a NAS system and a SAN Network

Sam Guiliano
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When two technologies have a similar function and a similar name, they can easily be confused. A typical source of confusion is the two common storage systems, NAS (which stands for network attached storage) and SAN (storage area network). Both of these solutions connect with a network and store files and databases for machines in the network. Cloud server versions of the two perform the same function virtually rather than physically.

Although the similarities between this pair of concepts are obvious, there are significant factors separating them as well. To keep things simple below, we will discuss each storage framework in its basic (non-cloud) form.

NAS (network attached storage)

A NAS is, theoretically, incredibly simple. It is made up of a hard drive or number of hard drives, an OS (operating system, typically Linux or Windows), and Ethernet connecting the hard drives to a network. A NAS has various benefits. Using network attached storage, a user or network administrator can share devices (such as printers), files and other data, and gigabytes of backup storage room.

File sharing – Let’s say you have NAS set up for your home computers, Computer A and Computer B. If you save a file to Computer A and have the NAS configured to save the file as well, you can access a folder within the NAS on Computer B and immediately have access to the most recent version of the file.

Infrastructurally in this situation, the NAS is connected directly to the router so that each of your devices can access it. Like an external hard drive or thumb drive, adding and removing items from the NAS can be conducted manually as well by grabbing files and dragging them into and out of the network attached storage folder.

Device sharing – Many of us use a printer that has a Wi-Fi connection, but sometimes we connect the device – let’s say a cell phone – to Computer A that we want available to Computer B as well. You can plug the cell phone directly into a NAS system such as GoFlex Home, and both Computer A and Computer B can connect directly to the cell phone to access photos, music, etc..

Backup storing – No one wants to lose their files, and most of us have experienced a devastating computer crash. Backup on a consistent and regular basis is critical. Nonetheless, Greg Falgiano, a senior product marketing manager at the hard drive and storage company Seagate, notes that backing up our devices is “like flossing”: it’s something we know is essential but is easy to overlook. NAS makes the backup process consistent and predictable when it is configured to occur automatically.

SAN (storage area network)

A storage area network, as noted above, is virtually identical to network attached storage functionally. The Storage Networking Industry Association (SNIA) defines a SAN as a network that facilitates transmission of data between machines used for storage and other devices. SNIA notes the finer points of how a SAN should be understood:

  • It is not necessarily limited to performing storage-related activities. A storage area network can respond to other user requests and serve additional system management duties as well.
  • A SAN does not necessarily have to be connected to other devices via Ethernet or Fibre Channel (FC), although the latter is a standardized method used by many enterprises for their storage area networks.
  • The machines used for storage can be of various types, such as disk drives, file servers, or RAID subsystems. Innovation in the SAN field are producing groundbreaking storage strategies and technologies, ideas and products that arise from needs for the fastest, most reliable, and most affordable SAN possible. Not all of these concepts will become commonplace, but the most viable ones are enhancing options for the storage of data.

Differences between a SAN & NAS system

Here are a few direct distinctions between SAN and NAS technology, courtesy of Everything VM:

  1. OS perception of storage – If the operating system on your computer perceives the storage framework as remote, typically network attached storage is involved. Network drives in Microsoft Windows are examples of NAS, accessible to just one user and limited in functionality. When a storage area network is accessed through Windows, on the other hand, Windows is unaware that the storage system is network-based. The SAN is perceived as if it were plugged directly into the computer, broadly accessible and capable of general drive functionalities.
  2. File level versus block level – When using NAS, access is at the file level. You can ask the NAS for something by name, and it will retrieve it. SAN access, though, is at the block level. A specific location of a file must be identified, and this is performed in terms of blocks. The client asks for blocks 5111-5133, for example. All data stored on those blocks is then transmitted.
  3. Complexity of shared access – Network-attached storage can easily be connected to more than one server, but performing the same setup for a storage area network is more complicated. This particular ease-of-use scenario is due to the file-level versus block-level difference. With a NAS sharing data at the file level, common issues such as checks for consistency and locks on files can be verified and resolved. Because SAN shares in terms of blocks, it leaves the OS responsible for specifics related to each block. That means file system configuration for a SAN must be completed carefully to avoid problems.

As you can see, SAN and NAS technology is generally similar, but the systems are far from identical. It’s not always a matter of choosing which one is best. Many organizations use hybrids of the two or combinations of each for storage. Talk to Atlantic.Net’s specialists today if you have any questions about how to set up storage for your IT infrastructure. We offer a managed cloud hosting storage service that is state of the art.
Difference Between NAS And SAN
Comic words by Kent Roberts and art by Leena Cruz.