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Storage area networks, or SANs, are a type of network to which multiple storage devices can be connected to provide networked users quick, reliable, and secure access to block-level storage. SANs rely on high-speed infrastructure to enable fast data transfer that mimics the experience of using local storage for end users. This article provides explains what a storage area network is, how it works, and the strengths and weaknesses of this type of storage solution compared to other storage solutions.
How Does a Storage Area Network (SAN) Work?
A SAN is a dedicated high-speed network that connects storage devices to servers. Built like other networks using cables, switches, and host bus adapters, SANs make it possible for every server on the network to access the storage devices in the shared pool as if they were attached directly.
In most enterprise use cases, the SAN is intentionally kept separate from the main user network, functioning instead as an independent network for all of the organization’s storage resources. This segregation optimizes network efficiency and mitigates data bottlenecks, making SANs a solid choice for geographically dispersed enterprises that handle critical data.
SAN architecture uses block-level storage, which keeps data in individual volumes, or blocks, similar to how mechanical hard disk drives (HDDs) work. This is particularly useful for more segmented databases, like those used by email servers or social media accounts, because these types of applications typically demand swift and direct around-the-clock access to their data.
Both the functionality and effectiveness of a SAN solution rely heavily on its base architecture. Different types of SANs offer a variety of approaches to meet a wide range of needs for specific applications or businesses.
Types of SAN Solutions
SAN solutions rely on high-speed infrastructure to provide fast data transfer rates. Depending upon its underlying technology, different types of SANs are better-suited to different needs. Typically they’re divided into four types.
Fibre Channel Protocol (FCP)
The fibre channel protocol (FCP) SAN is one of the earliest and most widely used types, making up between 70 and 80 percent of the global SAN market. It uses a high-speed fibre channel network to ensure reliability, accessibility, and low latency for time-sensitive and mission-critical applications like databases and enterprise resource planning (ERP) systems.
The fibre channel protocols are embedded with small computer system interface (SCSI) commands that provide block-level control, allowing users to transfer data directly from the SAN’s storage to the server without intermediaries.
Learn more: Best Fibre Channel Hardware for SAN Deployments
Internet Small Computer System Interface (iSCSI)
iSCSI is a more versatile SAN solution that uses standard SCSI protocol for sharing block-oriented storage data over TCP/IP networks. It leverages existing Ethernet infrastructure rather than requiring an entirely new system, making it more cost-effective and easier to implement. This makes it particularly preferable for small to medium-sized businesses with limited budgets.
iSCSI storage devices appear as if they’re directly attached to the access server, allowing for seamless integration with existing systems. This results in more latency compared to FCP, but technological advancements in Ethernet infrastructure solutions are narrowing the gap.
Fibre Channel over Ethernet (FCoE)
The convergence of FCP and Ethernet technology lets users encapsulate fibre channels within existing Ethernet frames, allowing for the transmission of fibre channel traffic over Ethernet. FCoE combines both the reliability and low latency of FCP with the cost-effective, ease-of-use, and flexibility of Ethernet connections.
By consolidating data networks and storage, FCoE is able to streamline the data transmission infrastructure and reduce overall complexity. However, FCoE requires specialized network equipment, which may involve higher upfront costs compared to other SAN solutions.
Non-Volatile Memory Express over Fibre Channel (FC-NVMe)
Non-volatile memory express over fibre channel is flash-based data storage that combines the high-speed data transfer rates of fibre channel infrastructure with NVMe storage devices, resulting in a significant latency reduction and maximizing performance. Unlike traditional NVMe systems, which only support one serial command queue, FC-NVMe supports tens of thousands of simultaneous parallel queues.
This makes it incredibly advantageous for applications that rely heavily on fast data transfer and access—for example, real-time data analytics and high-frequency stock trading. While still a relatively new SAN technology, it’s continuing to rapidly evolve and could be used more frequently in the future of data storage.
Key Features and Functionality of SAN Solutions
Here are a few of the key features that make SANs stand out above other types of storage solutions.
High-Speed Data Transfer
The high speed and reliability of advanced fibre channel technology makes SANs ideal for effectively moving large volumes of data between storage devices, servers, and network centers.
Data Protection and Disaster Recovery
SANs use transfer protocols known for their robust data protection and recovery features, such as snapshots and replication. In the unfortunate event of a disaster, SANs provide reliable recovery options that minimize unplanned downtime and prevent permanent data loss.
Centralized Data Management
SANs offer a centralized, unified storage pool that’s easy to access and manage. They streamline storage administration tasks and make it more efficient to optimize existing resources and simplify monitoring, reporting, and troubleshooting efforts, enhancing the overall maintenance of the infrastructure.
Scalability and Flexibility
SANs infrastructure can grow with storage needs by adding more storage devices to the network. It also supports technologies like storage virtualization, which further enhances the infrastructure’s flexibility, allowing administrators to allocate storage resources as needed.
SAN Infrastructure Drawbacks
Despite SAN’s numerous advantages and capabilities, it’s important to be aware of its drawbacks. Here are the most common:
- Cost—Implementing a SAN can be expensive, especially for smaller companies with limited resources.
- Complexity—SANs can be complex to set up, manage, and maintain, requiring skilled IT professionals with specialized expertise.
- Single Point of Failure—If not redundantly designed, SANs can become a network’s single point of failure, leading to unplanned downtime and data inaccessibility.
- Limited File Sharing—Since SANs provide primarily block-level storage, they tend to struggle with large-scale file-sharing and collaboration.
- Performance Bottlenecks—SANs’ performance may be limited by outside factors including network congestion, data connection, or disk quality, leading to problems with data transfer and delivery.
SAN vs. NAS
Network-attached storage (NAS) devices are standalone devices that contain solid state drives (SSDs) or HDDs. When connected directly to an ethernet switch, users can access them over the network—much like saving and retrieving files from a local drive. Most NAS devices use their own operating systems, which means users can add applications for security, surveillance, media streaming, printing, and data recovery.
While SANs excel in high-performance applications, offering block-level storage for efficient and fast data access, NAS systems are better suited for data-sharing collaboration, providing file-level storage simplicity for multiple-user infrastructures.
When it comes to performance, SAN architecture often outshines NAS due to the variety of high-speed data transfer options available. This makes it ideal for critical and data-intensive workloads and applications. But NAS systems are easier to manage and maintain, offering a more cost-effective option for businesses with fewer storage needs.
As for scalability, both SAN’s block-level storage and NAS’s file-level storage provide great levels of flexibility and easy expansion. Choosing between the two options should depend on priorities and storage requirements; understanding each type of storage’s unique capabilities would enable businesses to make informed decisions and implement the most suitable option.
Bottom Line: Storage Area Networks (SAN)
Because of their flexibility and performance, SANs are used across a wide variety of industries. In the finance and banking industries, for example, a SAN can speed up transaction processing and provide customers with real-time data access when trading stocks or tracking personal finances and assets.
In the media and entertainment industries, SANs are often employed for high-speed data transfer and storage critical for high-definition video editing and broadcasting. In the field of education, SANs are used to store and manage large volumes of student data.
SANs are an invaluable tool for businesses dealing with large amounts of data. Understanding the advantages and use cases of the different types of SANs and how they compare to other storage solutions is paramount to choosing the best one to meet your organization’s needs.
Read next: NAS vs. SAN: Differences and Use Cases
