What Is a Storage Area Network (SAN)?

A storage area network (SAN) is a high-speed network that connects a shared pool of storage devices to multiple servers. Each server can access the shared storage similar to a directly attached drive. A SAN offers scalability, high-performance data access, and centralized management for diverse storage needs. However, modern enterprises are moving away from SANs and selecting cloud storage options for their added flexibility, cost efficiency, and unlimited volume.

A storage area network provides block-level access to storage devices through specific protocols, providing efficient data storage, retrieval, and management. We give some use cases below.

Disk usage optimization

A storage area network connects many disk drives and other storage devices into one network. You have more control over your storage network as a single, centralized unit. You can assign specific storage units to certain servers, devices, or users. You can also employ dynamic tiering to move data between storage tiers without disrupting the network. The dynamic range of features and tiers you can use and configure in SANs allows you to optimize existing disk usage more effectively.

Data management

Storage area networks are commonly used in environments with transaction-heavy databases, such as those in banking, e-commerce, or corporate IT systems. The high-speed network and block-level storage provided by SANs are essential for handling the intense I/O demands of these databases. You can also automate several data management tasks in a storage area network. For example, you can create automatic backup routines, or initiate backup processes even while using the system.

Media processing

In the media and entertainment industry, particularly in video production and editing, SANs are used to store and manage large multimedia files. The high throughput and capacity of SANs are ideal for handling high-resolution video files, providing real-time access and editing capabilities. Similarly, SANs are used for storing and accessing large medical imaging files, like MRI and CT scans.

File sharing

In large organizations, storage area networks facilitate centralized file sharing across different departments and locations. This use case is particularly relevant for multinational corporations where data accessibility and consistency across geographies are crucial.

Backup and recovery

As a storage area network has several features to reduce downtime, it provides a highly available data repository. For instance, SANs can mirror data to multiple locations, providing redundancy while ensuring data is preserved and can be recovered quickly in the event of a system failure or disaster. Organizations use disaster recovery features to help protect against data loss in the case of an emergency.

The key components in SAN architecture are as follows.

Storage devices

Storage devices, or targets, are tape libraries, disk arrays, and solid-state storage systems. Each storage device typically has a range of interfaces and controllers that allow it to connect to the storage area network and communicate.

A SAN host is a server or computing device that manages data access and storage requests on the SAN. Hosts initiate all data storage requests and then access storage resources on the SAN. They access storage devices to read and write data.

Network protocols

SANs use several protocols to facilitate communication. For example:

• Fibre Channel Protocol is known for its high speed and reliability, making it suitable for demanding environments.

• Internet Small Computer System Interface (iSCSI) utilizes existing IP networks to reduce costs and complexity.

• Fiber Channel over Ethernet (FCoE) combines the high speed of Fibre Channel with the ubiquity of Ethernet, allowing for efficient integration with existing network infrastructures.

Each of these protocols serves to enhance the performance and scalability of SANs, ensuring efficient data transfer and accessibility across a networked storage environment.

Network components

A SAN also uses physical network components like SAN switches, directors, controllers, and gateways. These SAN components allow hosts to connect and communicate with different devices simultaneously. By switching between various storage devices, SANs can provide scalability and redundancy. The controllers and gateways facilitate communication along channels by connecting different types of storage networks. They use the protocols mentioned earlier to allow these communication pathways.

Storage management software

Storage management software allows you to administrate and manage SAN architecture and infrastructure. This software includes various tools that allow you to configure SAN components, manage provisioning, monitor performance, and ensure data integrity and security across the network.

In some SAN architectures, virtualization technologies transform physical storage into virtualized storage. Virtualized resources are easier to manage and have more data mobility.

Once you have connected your storage devices to your storage area network with all other components, it is ready to provide data storage and retrieval. The block-based storage in SAN holds data in a range of blocks called logical disk units or logical unit numbers (LUNs). You can store data on a LUN, like on a local area network or disk. The SAN connects these LUNs with requests, transferring the necessary block.

When you send a request to access data, the network sends a request through the SAN to the storage block where the data is. The SAN transfers the blocks of data that contain the information you are looking for from the storage device to the requesting server. While transferring, the SAN optimizes data transfer speeds to provide reliable retrieval speed.

Storage area networks use centralized management tools to monitor this stage effectively and manage all related resources. The network is divided into three layers for management, which we explain below.

SAN layers

The first SAN layer is the host layer. The host layer manages SAN connectivity and requests to block storage and databases. This layer uses connectors to handle requests and communicate between storage data and storage resources.

The second SAN layer is the fabric layer. The fabric layer includes network devices and cabling. This layer provides different routes for traffic, ensuring hosts have access to all of the storage attached to the network.

The third SAN layer is the storage layer. The storage layer represents all data storage devices like hard drives, CDs, tape arrays, and drives.

There are several limitations of SAN storage, which result in many businesses moving their workloads to the cloud.

Cost

Several SAN components—like storage arrays, host bus adapters, and fiber channel switches—are costly to install and maintain. Due to these costs, the initial SAN setup can be expensive. Equally, ongoing SAN maintenance can be costly for your business.

Complexity

A SAN storage system has to manage multiple servers and hosts. Maintaining and configuring this network to ensure all components work together can be challenging. SANs require expertise and experience to administrate, which can challenge organizations not equipped with the right skills and personnel to manage them. Due to the complexity of SANs, some businesses have moved to third-party cloud storage. You can access fully managed cloud storage, getting increased storage capacity without the complexities of SAN management.

Potential points of failure

In the SAN ecosystem, if a controller or a switch fails, it can create problems across the entire infrastructure. These small issues can create larger issues with accessing data, reducing availability.

Scalability

As organizations need to continuously store growing volumes of data, they must be able to count on the scalability of their storage systems. SAN storage does provide some scalability but requires meticulous planning to configure devices and maintain top performance. Organizations that want unlimited scalability switch to cloud-based solutions to increase storage volume on-demand and instantly.

A storage area network (SAN) and network-attached storage (NAS) both provide storage solutions. However, SAN storage is ideal for high-performance environments where low latency is key. Larger enterprises opt for SAN over NAS due to the higher scalability and performance.

On the other hand, NAS is appropriate for file sharing and data backup within smaller or medium-sized businesses. NAS is more cost-effective and easier to use than SAN, making it useful for newer businesses.

NAS and SAN are both networked storage systems. They contrast direct attached storage (DAS), a smaller-scale dedicated network system with a limited number of possible host connections and ports.

Amazon Web Services (AWS) offers services that provide cloud-based storage, surpassing the capabilities of SAN. For example, Amazon Elastic Block Store (Amazon EBS) offers cloud-based block storage services. You can migrate on-premises SAN workloads to the cloud for mission-critical applications. EBS stores data at a lower cost without compromising performance.

With Amazon EBS, you can:

• Scale your most demanding high-performance workloads, including mission-critical workloads.

• Protect against failures using replication within Availability Zones and access high durability.

• Select from flexible storage options to best suit your particular workload.

Get started with high-performance cloud-based storage on AWS by creating a free account today.