What Is a Storage Area Network (SAN) and How Does It Work?

Data volumes keep growing at astronomical rates. Corporations need to supply users with fast, simple access to vital information. Traditionally, users had to go through a server to reach their data. Providing direct access over a storage area network (SAN) boosts performance, simplifies management, and enhances reliability.

Legacy Storage Options

The amount of data generated today is mind-boggling. Data storage has been progressively increasing worldwide, from 64.2 zettabytes in 2020 to 147 zettabytes in 2024. The world is on pace to reach 181 zettabytes by 2025.

Corporations are awash in information. As data volumes have grown, the way they store and provide users with access has changed.

Legacy systems relied on direct attached storage (DAS) to deliver information. A server managed interactions with the data storage systems connected to it. Bottlenecks arose because the speed at which information moved from one system to another was constrained by the physical connection between the two.

Network-based storage offered a better option. This approach pooled data and allowed more than one computer to grab it through a network, improving data sharing and collaboration.

Two types of network storage emerged. Network attached storage (NAS) collects data in a single device made up of redundant storage containers or a redundant array of independent disks (RAID).

This technique is easy to set up. Users typically access the data over an IP network. However, this design does not scale well because it’s constrained by the device’s processing power.

What Is a Storage Area Network?

A storage area network (SAN) is a dedicated network of storage devices that provide a pool of shared storage servers that multiple computers and servers can access. Storing data in a centralized shared storage architecture like a SAN allows organizations to manage storage from a collective place and apply consistent policies for security, data protection, and disaster recovery. SANs network multiple devices so they offer more storage space and faster speeds than a NAS. They work well with large data sets, lots of users, and complex workloads. Another plus is a SAN eliminates single points of failure. As a result, they improve reliability and system availability.

Three Components in a SAN

A SAN includes three pieces of equipment that work together to deliver data to users: 

Network Interface Card (NIC)

A network interface card (NIC) is a specialized circuit board that connects storage systems to a network, either wired (Ethernet) or wireless (Wi-Fi). This hardware component ensures communication between storage devices and the rest of the network, facilitating data delivery to users.

Storage Devices

Depending on application requirements or company needs, various storage devices are deployed within a SAN. These devices house the information and can include hard-disk drives (HDDs), solid-state drives (SSDs), flash storage, and hybrid storage options. The choice of storage technology impacts the speed, capacity, and efficiency of the SAN.

SAN Switches

SAN switches play a critical role in connecting servers to storage devices and managing the data flow within the network. This hardware can include hubs, switches, gateways, directors, and routers. They work in tandem with SAN management software, which monitors and optimizes the performance of the entire storage network.

How Does a SAN Work?

The components of SAN include cabling, host bus adapters, and SAN switches attached to storage arrays and servers. SANs use block-based storage and high-speed architecture to connect servers to logical disk units (LUNs), a range of block storage from a pool of shared storage, and appear to the server as a logical disk. 

A SAN comprises three distinct layers: host, fabric, and storage.

Host Layer

The host layer is made up of the servers attached to the SAN, which run enterprise workloads that require access to storage (e.g., databases). 

SAN hosts use host bus adapters (HBAs), separate network adapters dedicated to SAN access, to interface with a server’s operating system. This allows a workload to communicate storage commands and data to the SAN and its storage resources using the operating system.

Fabric Layer

The fabric layer comprises the cabling and network devices that make up the network fabric that interconnects SAN hosts and storage. SAN networking devices can include SAN switches, gateways, routers, and protocol bridges.

The fabric layer offers increased redundancy over a regular network by providing multiple alternate pathways from hosts to storage across the fabric. This means that if there’s a disruption on one path, the SAN can use an alternative path for communication.

Storage Layer

The storage layer comprises several storage devices, which are typically HDDs but can include SSDs, CDs, DVDs, and tape drives. Storage devices within a SAN can be organized into RAID groups to increase storage capacity and improve reliability.

SAN Protocols

A storage area network protocol determines how devices and switches communicate with each other. A SAN can use one protocol or many because multiprotocol routers and switches move information from place to place in different ways. SAN technologies support multiple protocols that allow the layers, applications, and operating systems to communicate. The most common protocol used is the Fibre Channel Protocol (FCP), which is based on Fibre Channel (FC) technology. Internet Small Computing System Interface (iSCSI), a less expensive alternative to FC, is commonly used by small and medium-sized organizations. Let’s take a closer look at the different types of SAN connections.

Internet Small Computer System Interface (iSCSI)

The Internet Small Computer System Interface (iSCSI) is an IP-based standard that links data storage devices over a network. Familiarity is an attraction. Enterprises use the same networking protocols for storage, storage management, and data networks, which simplifies system management.

Fibre Channel Protocol (FCP)

The Fibre Channel Protocol (FCP) is a gigabit-speed network technology primarily used for storage networking. The protocol was developed for supercomputers but became a common standard in enterprise data centers.

Fibre Channel over Ethernet (FCoE)

Fibre Channel over Ethernet (FCoE) is a protocol to route FC packets over Ethernet networks. This approach simplifies management because the enterprise LAN and SAN share a common network infrastructure.

Fibre Channel over IP (FCIP)

Fibre Channel over IP (FCIP) is a tunneling approach. Here, Fibre Channel storage information is wrapped in TCP/IP network protocol. Many organizations have an existing IP infrastructure so they find being able to link geographically dispersed SANs at a relatively low cost attractive.

Benefits of Deploying a SAN

SANs are quite popular. Worldwide sales reached $19.4 billion in 2022 and are expected to increase to $52.3 billion in 2032, exhibiting a CAGR of 10.7% during that time. The popularity stems from SAN's numerous benefits.

Simpler Administration

A SAN centralizes storage devices. The clustering of system resources makes it easier and less expensive to administer infrastructure costs, lowering a firm’s total cost of ownership.

Improved Application Availability

Storage exists independently of applications and servers. Since it’s accessible through multiple paths, reliability increases and availability improves.

Better Application Performance

SANs offload storage processing from servers onto separate high-speed networks. Consequently, information retrieval occurs faster.

Enhanced Scalability

SANs make it simpler for companies to boost storage as needed. As a result, they scale more easily as the business grows.

Use Cases for SAN

Data drives corporate decision-making. Companies rely on SANs to provide data to employees, partners, and customers. This approach also enables them to protect information and ensure it’s available when needed. The technology supports all applications. A few common ones include:

Data Consolidation and Access

Historically, corporations managed data in a scattershot manner. Information was housed in autonomous applications. This approach led to a great deal of duplication and waste. A SAN collects information in a single place, which increases efficiency and the likelihood that users can access needed information.

Remote Site Data Transfer and Vaulting

Companies need to protect sensitive information. SANs enable them to create a remote copy of their data, which will be available if problems arise with the central system.

Accelerate Your SAN with All-flash Solutions from Everpure

SANs are an important part of a company’s technology infrastructure because they provide quick access to needed information. Large corporations rely on SANs to deliver information to users. Increasingly, small and medium businesses are deploying these devices to house their corporate data.

Everpure has several offerings that provide companies with robust, cost-effective solutions for block and file storage:

• FlashArray//X™: High-end and performance-focused for mission-critical environments
• FlashArray//XL™: Highest performance and scale for large enterprises needing massive storage and speed
• FlashArray//C™: Mid-range option balancing performance and cost for less critical workloads
• FlashArray//E™: Entry-level all-flash, targeting cost savings to replace traditional disk systems

For more information about how Everpure can help your company address its data needs, get your storage evaluation kit.