What Is SAN? Everything You Need To Know

Dusan Vasic

Updated: July 14, 2023

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A storage area network is a high-speed data transfer network that provides access to physically and logically centralized data. A SAN typically consists of one or more storage devices connected to one or more servers. 

The server can be connected to the SAN directly or through a network switch. This article will cover everything you need to know about SAN, how it works, and its pros and cons. 

The Definition of Storage Area Networks 

A storage area network is a group of storage devices and computers. They are connected via high-speed optical connection, so the data can be shared quickly.

This high-speed network is made up of switches transmitting data using a fibre channel protocol. It also includes optical fiber cables. SAN is unique because it uses a network to create a shared pool of storage devices. 

This network moves the data through different storage devices, which can be shared between the network servers, making quick connections for data backup possible. With it, data archiving, retrieval and restoration can be done quickly. 

Although the many devices of SAN are typically placed in one room, one of the perks of this network is that they can be located in different locations and connected even at long distances. 

How Does a SAN Network Operate? 

A SAN is a dedicated high-speed network that provides block-level storage access to servers. A SAN typically uses a storage controller that connects to the server over a high-speed channel (such as a 4 Gbps Fibre Channel or 10 Gbps Ethernet). 

The controller presents the storage devices (such as hard drives or solid-state drives) to the server as logical units. Or, more precisely, it gives each such disk a unique logical unit number. 

SAN is made of communication infrastructure, which allows any-to-any device connection within the network via interconnected elements, such as director switches. The SAN network provides physical connections and can be considered an extension of the bus concept. 

This technology has come a long way, and new methods for attaching storage to servers are being developed all the time.

Types of SAN

A SAN protocol determines how switches and devices communicate within a storage area network. These are the most common protocol types: 

1. Fibre Channel over Ethernet makes up less than 5% of all SANs. This is a protocol that routes FC packets over Ethernet. With it, the flexibility is improved, and the SAN infrastructure is simplified. Switching solutions for SANs and LANs is unnecessary because you use a single device, and both storage data and IP packets can be transferred.
2. Fibre Channel Over IP is sometimes referred to as storage tunneling or fibre channel tunneling. With it, the information can flow through the IP network. Many companies and organizations use it as it’s convenient for linking SANs in different locations for a relatively affordable price.
3. Fibre Channel Protocol is a faster-than-Ethernet connection, so systems that use it (such as workstations, mainframes, supercomputers, and displays) have faster and more reliable data transfers than local area networks connected through Ethernet.
4. Non-Volatile Memory Express over Fibre Channel is a storage protocol and host controller interface that accelerates data transfers between solid-state drives and enterprise and client systems over a PCI express interface. 

SAN Benefits

There are many benefits to using a SAN over other types of storage, such as direct-attached storage (DAS), including: 

• Increased performance: A SAN can provide much higher performance levels than DAS due to the increased bandwidth and lower latency than a dedicated storage network can offer. SAN moves and offloads storage processing to separate networks, which improves performance.
• Improved scalability: A SAN can be easily expanded by adding new storage controllers, switches, and drives, without making any changes to the server. It supports large deployments of SAN host servers, storage systems, and devices.
• Greater flexibility: A SAN can offer greater flexibility regarding the types of storage that can be used and the ability to connect multiple servers to the same storage devices. This can lead to increased utilization of storage resources and lower overall costs.
• Comprehensive management features: SAN supports various enterprise-class storage features such as storage replication, self-healing technologies, data encryption, and data deduplication, providing better resilience, storage capacity, and data security.
• Better data availability: Storage can be accessed via many paths, improving availability, serviceability, and reliability. A proper SAN deployment means that there are multiple ways to reach data at any time, so even if some pathways fail due to servers being down, there will be other ways to obtain the necessary files.

SAN Drawbacks

Although SAN has many benefits, it is still far from perfect. There is much room for improvement, and we’ll mention the two most significant disadvantages to consider if you’re unsure whether to integrate SAN with your business. 

• Scale. Given the price, SAN is convenient only for bigger enterprises with multiple servers and significant storage requirements. While it is possible to use it on a smaller scale, it probably wouldn’t be optimal for small businesses due to its high cost. Instead, most small businesses and individuals might want to rely on cloud storage solutions as they are often more affordable and easier to manage.
• Management. It is sometimes difficult for busy companies to configure features like zoning or LUN mapping. Moreover, setting up RAID and other technologies can be very time-consuming. 

SAN Use Cases

SAN is a network usually used by businesses that need extra assistance in protecting their data and improving their performance. Here are some use cases:

• SAP, ERP, and CRM environments. SAN is great for planning the usage of company resources and customer management at an enterprise level.
• Oracle databases. Oracle databases typically require high availability and performance, so SAN is often an excellent solution for use with them. The same goes for Microsoft SQL server databases. 

Conclusion 

SAN is a great storage solution for businesses that require high data availability and quick data transfers. It is easy to scale and manage and offers many features that improve transfer speeds, security, and data resilience. Keep in mind that SANs can be pretty expensive, which is why they might not be the best solution for small businesses.