What Is SAN (Storage Area Network)? Meaning, Features, and Use Cases
A storage area network helps store and consolidate block-level data using a pool of connected devices.
Storage area network or SAN is defined as a way to store block-level data in a consolidated manner, using a pool of devices that connect to disks, tapes, etc., from the main server so that the operating system (OS) considers SAN the same as directly connected storage. This document defines storage area network and its key features. It also describes the components of a storage area network and its use cases.
Table of Contents
What Is SAN?
Storage area network or SAN is defined as a way to store block-level data in a consolidated manner, using a pool of devices that connect to disks, tapes, etc., from the main server so that the operating system (OS) considers SAN the same as directly connected storage.
A storage area network (SAN) is a specifically-designed network of storage devices that provides several PCs and servers with a shared storage pool. It establishes a single storage pool and encourages the centralization and consolidation of data.
It is often connected via Fiber Channel (FC) networks. The primary purpose of SAN is to transfer data between the server and the storage device. It also allows data to be shared between the storage systems.
Information in organizations is expanding at an accelerated rate. Organizations currently use storage systems to store this data. This data must be effectively handled, optimized, safeguarded, and stored.
A practical storage system must provide just-in-time information to users, integrate information infrastructure with organization processes without compromising on security or integrity, and provide flexible and resilient storage architecture that aligns with changing demands of the organizations. The storage system should be highly scalable without compromising the application’s performance.
SAN technology is an excellent option for business-critical applications that need high throughput and low latency. SANs are meant to eliminate individual points of failure, which increases their availability and resilience.
Components of SAN architecture
There are three essential components of SAN: servers, storage, and network infrastructure. These components are divided into vital elements such as node ports, storage arrays, cabling, interconnecting devices, and SAN management software.
- Node ports
Nodes are units that function as a source or endpoint for several nodes in a fiber channel. These include servers, memory, and tape libraries, among others. Each node has, at a minimum, one or more ports that allow communication with other nodes. Ports send data in full duplex mode using a transmit (Tx) channel as well as a receive (Rx) connection.
- Cabling
SAN structures use optical fiber cabling to transfer data. There are two varieties of optical cables.
- Multi-mode fiber (MMF): The MMF cable transmits light beams directed at diverse angles, yet simultaneously onto the fiber cable’s core. After a set distance, light beams flowing through these wires often disperse and clash, diminishing signal power and modal dispersion. Thus, the MMF cables are suitable for shorter lengths, up to 500 meters.
- Single-mode fiber (SMF) cable: The SMF cable transfers a single light beam through the fiber’s core. The small core in the cable reduces modal dispersion. Thus, the SMF cables can transmit data for longer lengths of up to 10 kilometers.
- Interconnected devices
The devices most often linked in SAN are ports, network switches, and directors. In fiber applications, hubs are employed as communication devices to physically connect several nodes in a rational loop or star architecture. Switches are smarter than hubs because they transmit data straight from one terminal to another. Directors are more prominent when compared to switches and are utilized to create data center networks. They have higher fault tolerance and port count than switches.
- SAN management software
The SAN management software manages the interface between the host, storage arrays, and interconnection devices. The SAN administration software includes essential management operations like connecting storage systems, switches, and zoning, which is the logical division of the SAN. It also manages important elements of SAN, like storage devices and interconnection devices.
- Storage array
A storage array is a system to store block, object, or file-based data. A SAN’s primary goal is to give the host access to storage resources. SAN storage implementations offer the host improved performance, high availability and redundancy, business continuity, and multiple-host connectivity.
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How does SAN work?
SANs connect servers to logical disk units (LUNs) using high-speed architecture and block-based storage. SAN technologies support multiple protocols, enabling communication between operating systems, layers, and applications.
The fiber channel protocol (FCP), based on fiber channel (FC) technology, is the most widely used. Small and medium-sized businesses frequently employ internet small computing system interface (iSCSI), a less expensive substitute for FC. Fiber channel over ethernet (FCoE) is another less-used protocol. Also, the non-volatile memory express over fiber channel (FC-NVMe) protocol supports several parallel queues.
A SAN consists of three distinct layers:
- The host layer. This layer comprises servers with SAN connectivity. It allows organized workloads that require access to block storage, such as databases. SAN hosts use host bus connectors to interact with a server’s operating system, allowing workloads to communicate storage data and instructions to the SAN and its storage resources via the operating system.
- Fabric layer. This layer comprises communication media such as cabling and network devices used for SANs to interconnect the hosts with storage devices. It provides multiple routes for traffic from hosts to storage across the fabric, thus offering increased redundancy.
- Storage layer. This layer comprises a collection of storage resources for different storage pools and layers. These devices include hard drives, standard drives, tape arrays, and CDs.
How is SAN different from NAS?
SAN and NAS are storage systems. The primary distinction is how each reads, stores, and retains data. SAN stores structured workloads as blocks, while NAS stores unstructured workloads as files. SAN connects several data storage devices through fiber channels, while NAS is a physical device that connects to a local area network (LAN) via an Ethernet connection.
Additionally, the file system in SAN is managed and controlled by its servers, while the file system in NAS is governed by its head unit.
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12 Key Features Of SAN
The following are the key features of storage area networks:
1. Scalability
SANs allow users to conveniently add or remove storage devices from their storage networking systems, making it easier for them to scale up or down the storage space to meet their demands. Additionally, servers run without interruption during scaling up or down. As users do not have to reboot or stop these servers, it allows the applications to keep running, thus minimizing downtime.
2. Security features
Data stored in a storage system is at risk of getting compromised by cyber attackers. That is why a sound storage network system must have excellent security features. SANs have great security features. SANs allow users to use a virtual SAN to restrict access to data without authorization.
SANs have data protection algorithms that are executed in one place to ensure that security and compliance configurations are consistently applied to all the servers in the SAN. They also have security protocols, such as an access control list (ACL), which makes them one of the best storage networking systems.
3. Improved disk utilization
SAN has a better and enhanced disk utilization system. In SAN, all storage disks are connected using a centralized network which ensures that multiple disk drives in a network are recognized as a single unit even though users can utilize the disk drives separately.
Using a centralized network gives the user more control over their network as they can manage the storage devices at the neural level or assign a specific storage device to a particular server. SANs also have another feature known as dynamic tiering. Dynamic tiering allows users to transfer or move data between different storage tiers with minimal interruption to the network. This feature is helpful as it improves disk utilization. It also ensures that users can transfer data without experiencing application or host outages.
4. Failproof disaster recovery
SANs are equipped with a disaster recovery feature. This feature allows users to recover data from the backup system in cases where the data gets lost or erased. The disaster recovery system can also be used as a backup network system whenever a server experiences downtime or a storage disk crashes. Although implementing some disaster recovery measures could prove expensive, it is best practice to have a disaster recovery plan rather than risk losing all the data.
5. Minimal downtime
Organizations that use SANs guarantee that their applications or databases will not experience downtimes or crashes due to performance-related issues. With SANs, servers also don’t have to be frequently reset or stopped, and organizations can expect industry-standard uptime.
6. Ultra-fast data transfer
SANs are one of the fastest storage networking systems. They can use fiber optic cables such as standard or lucent connectors with high data transmission speeds of up to 1 Gbps and 4 Gbps, respectively. Meanwhile, other technologies, such as network attached storage (NAS) and direct attached storage (DAS), use standard data transfer equipment, which transfers data at relatively slower rates.
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7. Data deduplication
When dealing with large amounts of data, it is common to encounter duplicated data blocks that take up additional space on the storage network systems. SANs are equipped with a data deduplication feature. This feature allows the SAN to detect duplicated data and remove it to free up more space.
The data deduplication process works in two ways, post-process and inline. The post-process function searches for duplicate data blocks after they are written on the disk and automatically removes them. However, the inline process functions like a filter. It automatically removes duplicate data before it is written to the disks.
8. Easy backup
SANs have a centralized backup system. SANs are automatically set up such that if one server or a disk storage device malfunctions or stops working as expected, the centralized backup system takes over and the entire network continues working normally without any interruptions. Moreover, the backup process happens in real-time; thus, downtime is reduced. They also use dynamic snapshots technology that allows faster and more dynamic data backing up.
9. Dynamic failover protection
In addition to having better redundancy and real-time traffic rerouting features, SANs are equipped with dynamic failover protection, allowing traffic rerouting to a stable network or server in case an issue occurs. The dynamic failover protection feature is also helpful during server maintenance. This feature enables the system to effectively manage the situation while ensuring the application is up and running.
10. Thin provisioning
Thin provisioning can also be called dynamic provisioning. This feature allows SANs to virtualize the storage disks. It enables users to allocate more storage space than they physically have in their SANs. This feature ensures efficient use of free storage space.
11. Application access
SANs allow users to access data through applications that are connected or installed on the network servers. Thus, users can access applications such as their billing systems from any location as authorized. This feature also allows organizations to choose the best data centers to store their information without getting restricted by their geographical locations.
12. Data management
An exemplary storage network should enable users to manage data more efficiently and simply. SANs allow users to automate a lot of tasks in the system. Additionally, with SANs, all the data is available at the block level, allowing users to restrict access to different accounts.
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5 SAN Use Cases
SANs are suitable for use in applications that require the transfer or movement of large amounts of data. Storage area networks are often deployed to support business-critical and performance-sensitive applications such as:
1. Databases
One of the most critical use cases of storage area networks is database and database management systems such as Oracle and Microsoft Structured Query Language (SQL) server databases. These systems are suited for use with SANs because they consistently sustain mission-critical workloads that process a significant number of transactions.
For example, database systems in specific applications process several thousand input-output operations per second, necessitating a storage solution with high input-output every second and low latency rates, in addition to the required scalability, stability, and availability.
A database system with a poor storage system that fails to meet its demands makes the application perform inefficiently, thus impacting user experience. However, with SANs, organizations can guarantee that their application performs well. The most recent fiber channel technology supports multilane capacity rates of up to 128 Gbps and, therefore, can fulfill throughput and latency requirements.
In addition, SANs provide parallel processing, low disc queuing, and reliability, alongside support for RAID and hot-swappable drives, all required for optimum data management.
2. Virtual desktop infrastructures (VDI)
For organizations, enhancing user experience is always a priority. SANs provide a VDI environment where multiple users can access their desktops simultaneously without downtime. To achieve this, the VDI environment must be highly available, secure, scalable, and reliable. It must also support VDI hosts deployed around the network. In addition to enabling virtualization, the VDI platform shares the same storage issues with server virtualization.
SANs, particularly those based on FC technology, offer the high capacity and low latencies needed for VDI storage systems, making VDI platforms a perfect application for storage area networks. SANs further provide a network infrastructure and a layer of protection to safeguard virtualization and associated data. Additionally, organizations may build expandable storage to satisfy rising PC demand.
3. Server virtualization
Now more than ever, organizations are using virtual servers to develop and test their products, host their database systems and websites, or business applications. The virtualization environments that host virtual machines (VMs) such as VMware or Microsoft Hyper-V and applications running on them all require fast, reliable, and flexible storage to accommodate highly dynamic environments.
Virtualized environments that host several applications require reliable infrastructure to curb multiple application outages, which may result from a single point of failure. As a result of the elimination of any singular system failure, SANs are incredibly durable and dependable, allowing virtual servers to function effectively as SAN applications.
Additionally, the scalability and flexibility of SANs allows them to minimize the need to redesign their infrastructure with every change that occurs in the virtualization environment.
4. Business applications
Business-critical applications such as enterprise resource planning (ERP) or customer relationship management (CRM) applications are supported by SANs. These applications utilize databases to handle the massive transactional data volumes they process. Consequently, they demand the exceptional performance and availability of SANs for storage systems. As they regularly download and distribute big video files over the network, video editors may also be required to use SANs.
The infrastructure of SANs enables these professionals to transfer large files at speeds of up to 4 Gbps using a variety of fiber optical cables. SANs are used to store enough data by organizations that use mission-critical systems like billing, sales, and reservations. SANs also have excellent security features that keep the data they transfer safe and help them keep secrets. They can also be set up with redundant parts throughout the storage infrastructure to ensure they are reliable.
5. Development and testing
The capacity to be flexible and reliable is typical of SANs. Highly varying storage requirements make them suitable for organizations to use during the development and testing of applications.
Development teams need different storage requirements at various stages of development. They must choose a storage system that meets their changing demands. These teams also need a safe storage system to protect the source code and other data. A SAN gives you a storage infrastructure that meets all of these requirements for development and testing. This helps speed up the development process.
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Takeaway
In recent years, cloud storage has begun to replace SAN, although the latter remains a popular storage model for many organizations relying on on-premise systems. That is why it is crucial to know the meaning of storage area networks and how they work, as well as ways to make them more secure against vulnerabilities. A robust SAN system can prove to be a crucial enabler for your enterprise and provide ready-to-use data on-premise with scalability and ease of access.
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