Storage Networking

Storage networking is the practice of linking together storage devices and connecting them to other IT networks. Storage networks provide a centralized repository for digital data that can be accessed by many users, and they use high-speed connections to provide fast performance. It’s most common to find storage networks in enterprise settings, although some vendors do sell networked storage products for consumers and small businesses.
Storage Networking and SAN

The phrase “storage networking” is commonly used in reference to storage area networks (SANs). A SAN links together multiple storage devices and provides block-level storage that can be accessed by servers.

Some people also use the phrase “storage networking” in reference to network attached storage (NAS) devices. Similar to a file server, a NAS array is a standalone device that connects to a network and provides file-level storage that can be accessed by end users.

The benefits of storage networking can include improved performance, reliability and availability. It can enable greater collaboration among workers, and it can simplify some IT management tasks. Storage networks also make it easier to back up data for compliance and disaster recovery purposes. In addition, they can free up valuable server CPU cycles for more important tasks. And although setting up a storage network can be costly, in some cases, it can reduce overall storage costs.
Storage and Other Networks

Storage networking is very similar to other kinds of IT networking. Just as you can connect multiple PCs and servers into a local area network (LAN) or a wide area network (WAN), you can connect multiple storage arrays into a storage area network (SAN).

SANs are often confused with the other common kind of networked storage — NAS devices. In a nutshell, the difference between SAN and NAS is that a SAN is a network, while a NAS array is a device connected to a network. End users don’t save files directly to SANs. Instead, SANs store blocks of data for access by the applications running on servers. By contrast, end users can save files directly to NAS devices.

Making things somewhat more confusing, the lines between SAN and NAS devices are beginning to blur as some vendors release storage appliances with a combination of SAN and NAS capabilities. Many organizations use both SANs and NAS devices, and some connect NAS arrays to their SANs.

The alternative to networked storage is direct attached storage (DAS). Before the advent of storage networking, DAS was the only option for saving digital information. With DAS, a storage device is connected directly to a server or a PC, not to a network. Familiar examples of DAS include a desktop or laptop hard drive, a CD-ROM, a USB memory stick and a hard drive attached directly to an individual server.
Storage Networking Implementation

The process for setting up a storage network will vary depending on whether you are deploying a SAN or a NAS device. Generally, NAS devices are easier to deploy. They connect directly to a LAN via a TCP/IP connection. Some NAS arrays sold for home or small business networks are so easy to deploy that it takes only a few minutes to plug in the cables and configure the network before the devices are up and running.

Deploying a SAN, on the other hand, can be much more complicated. You can create a simple SAN with a storage device, a SAN controller and the appropriate cables. However, in data center environments, a typical SAN will include multiple storage devices, controllers, and networking gear like routers, switches, bridges and gateways, much like you would find in a LAN or WAN. The exact design of the SAN will depend on the needs of the organization and the types of hardware in use. SANs can use a variety of communication protocols, including Fibre Channel (the most common), iSCSI, ATA over Ethernet (AoE), Fibre Channel over Ethernet (FCoE), ESCON over Fibre Channel, HyperSCSI and others.

Storage networks are often used alongside storage management technologies, such as storage resource management software, virtualization, mirroring, and compression.
Storage Networking Technology

An organization called the Storage Networking Industry Association (SNIA) promotes storage networking and establishes standards designed to grow the industry. This group has published the Storage Management Initiative Specification (SMI-S) and numerous related standards.

Another group, the Fibre Channel Industry Association (FCIA), also promotes storage networking and data storage, video, networking and storage area networking (SAN) management technology.