What Is A Storage Area Network (SAN)?

A storage area network (SAN) is a dedicated and high-speed network that interconnects pools of storage devices and delivers these devices for access by multiple servers. SANs provide the consolidated storage required in enterprise computing with various inherent advantages.

Better Organization and Management: The technology allows for managing cohesive storage pools.
Improved Security: The storage can be centrally protected as per internal and external regulations and standards. Central deployment of data protection algorithms enhances data security and regulatory compliance.
Improved Storage Availability: In the event of failure on a device or cable, storage remains accessible to workloads as alternative paths within the SAN network exist. This ensures business continuity at all times.
Flexibility and Scalability: SANs are highly flexible and can be scaled to meet the growing needs of an enterprise. Optimizing the storage capacity is relatively easy to implement with a redundant array of independent disks (RAID), data deduplication, and similar additional technologies.

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Setting Up A Storage Area Network

A SAN assembly comprises storage devices, hosts, and switches interconnected using various protocols and topologies. Integrating these components requires that an enterprise meets the vendor’s hardware and software compatibility requirements.

Setting up a storage area network follows the following straightforward process:

Assemble and interconnect the network’s hardware components
Install and run the corresponding software on the various devices
Configure the network, making any adjustments as may be required
Test the assembly or integration. Ensure you cover all operational processes that are characteristic of the SAN environment from normal operation to failure mode
Establish and document a performance baseline not just for the network, but also for the individual components
Document the installation and operation standards and procedures for your SAN

How It Works: Architecture And Operation

SANs ensure high availability and performance of storage by attaching to multiple servers. They comprise 3 distinct layers.

The Host Layer: This layer comprises the servers attached to the SAN. Servers, that is, the hosts, typically use LAN or ethernet for communication with each other and users. SAN also employs a separate network adapter, called a host bus adapter (HBA), dedicated to SAN access. Once configured, the HBA allows the enterprise workload to send out commands and data to the SAN.
Fabric Layer: This layer comprises the network devices and cabling interconnecting the SAN storage and hosts. The devices include SAN switches, gateways, protocol bridges, and routers. The architecture of the fabric layer is such that there are multiple paths for storage area network communication. In the event of disruption on any one path, SAN communication continues with an alternative path.
Storage Layer: From magnetic HDDs to SSDs, DVD drives, tape drivers, and CDs, this layer comprises the different storage devices. The devices are collected into different types and tiers. Each storage entity is assigned a logical unit number (LUN), an identifier through which the hosts can access the storage devices.

With SANs, high-speed data transfer between storage devices and servers is possible in 3 ways.

1. Server To Storage

In this interaction model, multiple servers can access a storage device serially or concurrently.

2. Server To Server

A SAN, through a server-to-server interaction model, ensures that the communication remains high-speed for high-volume communications.

3. Storage To Storage

SANs make it possible to move data across different storage devices without server intervention. A good example of this interaction model is when a disk drive backs up its own data to a tape device. This requires no intervention from the server, freeing the server for other functions such as application processing.

Get Started

With a clear understanding of what a storage area network is, and its many advantages, there is no reason to delay setting up a storage area network for your enterprise.