SAN (Storage Area Network)
WHAT IS SAN (STORAGE AREA NETWORK)?
SAN (storage area network) is a common storage networking architecture that delivers a high throughput and low latency for business-critical applications.
What are the benefits of SANs?
Used by a majority of enterprises, a storage area network commonly stores an organization’s vital customer data across segregated devices and servers on a virtual network. SANs off-load storage function to improve efficiency and isolate failures should they occur. Organizations also use a SAN to enhance business-critical application performance, making the applications more readily available and improving utilization rates.
SANs store data in blocks, dividing them into separate tiers in a high-speed architecture with consistent security practices across the network. This provides more effective data storage and improved data protection and security.
What is the difference between SAN and block storage?
SAN and block storage are often confused because SAN is a method of delivering block storage — they are closely connected and frequently discussed together in IT infrastructure contexts.
Why are they often confused?
- Intertwined functionality
SAN provides block storage. When you’re using a SAN, what you’re actually consuming is block-level storage. Though the terms are sometimes used interchangeably, SAN refers to the network infrastructure and block storage to the storage model.
- Similar use cases
Both are used for high-performance, low-latency, and mission-critical workloads like databases, virtualization (VMs), and ERP systems. This shared purpose adds to the confusion.
- Shared protocols
Both use on fibre channel (FC) technology comprising technologies associated with block-level access. So when someone sets up a Fibre Channel SAN, they’re automatically dealing with block storage.
- Often packaged together
SAN architecture is often bundled with block storage offerings, leading people to view them as a single concept rather than distinct layers (network vs. storage method).
What do SANs and block storage have in common?
Common feature Description
Block-level access Both refer to storage that is accessed at the block level, not as files.
High performance Designed for speed and low latency, critical for enterprise environments.
Scalability Both are scalable solutions suited for growing data workloads.
Flexibility Allow multiple hosts to access storage concurrently when configured properly.
Logistical disk units (LUNs)
SANs connect servers to their logical disk units (LUNs), or blocks of storage, which present to the server as a logical disk. The server then partitions and formats these, often as all-flash storage, capitalizing on its high performance and low latency. Users access data and devices stored on a SAN just as if they were housed on a local area network (LAN).
Span physical sites
Storage area networks can span multiple sites and are often based on fibre channel (FC) technology. They use either fibre channel protocol (FCP) or proprietary variants depending on what kind of system is connecting to them. SAN storage is especially useful when several people need to connect to multiple storage devices at once.
SANs use four common protocols to transport data:
1. Fibre Channel Protocol (FCP) – Widely adopted, FCP uses the fibre channel network to send SCSI commands. It provides high-speed delivery of raw block data with no losses between computer storage and servers.
2. Internet Small Computer System Interface (iSCSI) – Used by about a tenth of enterprises, iSCSI has a lower cost than FCP. iSCSI maps block-oriented storage data using SCSI commands inside an Ethernet frame and then uses a standard TCP/IP Ethernet network for transport.
3. Fibre Channel over Ethernet (FCoE) – FCoE essentially places the FCP on a new physical link—an Ethernet link. Because of that simple switch, a SAN can use less hardware and cabling, with easier installation and management than traditional protocols. It is a standards-based protocol that also eliminates the need to run separate LAN and SAN networks.
4. Non-Volatile Memory Express Over Fibre Channel (FC-NVMe) – FC-NVMe is an interface protocol for accessing flash storage via a PCI Express (PCIe) bus. FC-NVMe offers vast performance improvements over traditional all-flash architectures (AHCI). While AHCI are limited to a single, serial command queue, NVMe can handle tens of thousands of parallel queues, each managing tens of thousands of simultaneous commands.
What is the difference between SAN and NAS?
Both SAN and NAS (network-attached storage) are methods of managing storage centrally and sharing out to multiple servers, but a few differences distinguish them from each other. Primarily, NAS is more abstracted than SAN storage. NAS partitions storage into files, folders, and volumes that are managed by a head unit, which means the data is entirely independent of the connected devices rather than being stored in blocks made up of logical unit numbers (LUNs) as in SAN.
Both also use different methods of sharing stored data: SAN shares to a dedicated network, while NAS uses a shared network. Additionally, SAN and NAS differ in their transport capabilities. NAS uses Ethernet, while SAN can use both Ethernet and Fibre Channel.
The benefits to each vary as well. SAN focuses on high performance and low latency, while NAS targets ease of use, manageability, scalability, and lower cost.
What are the protocols used by SAN and NAS?
Storage area networks use four protocols: FCP (Fibre Channel Protocol), iSCSI (Internet Small Computer System Interface), FCoE (Fibre Channel over Ethernet), and FC-NVMe (Non-Volatile Memory Express over Fibre Channel). When serving data using any SAN protocol, a user may need specialized hardware to transport storage area network traffic. For example, different switches and network cards might need to be deployed, or even converged network adapters (CNAs) that allow hosts to offload some CPU processing. These dedicated resources help to improve performance.
By contrast, NAS uses protocols shared by other types of servers (Windows and/or LINUX)—Common Internet File Services / Server Message Block (CIFS/SMB) and Network File System (NFS). These protocols make data storage easier to manage. They also allow the network to use infrastructure that already exists on the end user’s system.
How do organizations use SANs?
Companies that use SANs cut across industries, including education, retail, banking, telecommunications, insurance, financial services, media, and government agencies. However, the largest segments represented are in computer software, information technology and services, and hospitals and healthcare. These types of companies often rely on high performance computing requirements to run virtualization applications and hybrid multicloud operations and need the huge data storage capacity of SANs to handle their big data.
For example, computer software companies develop new products with an incessant stream of design, test, fail, and repeat until reaching just one viable option. This process entails hundreds if not thousands of iterations during development and that requires massive amounts of data storage.
Explore HPE’s SAN solutions
HPE has a vast storage portfolio and worldwide consulting and support services to help you connect data with a flexible, adaptable, and future-ready infrastructure. Our products are rigorously tested for compliance and configured for setup right out of the box.
With thousands of configurations, HPE storage products minimize fabric compliance issues and ensure that upgrades are validated to function with existing infrastructures. HPE is bringing the power of flash and other enterprise storage capabilities down to the price and simplicity levels that can benefit nearly any organization in the market for shared storage and the tools that are used to manage them.
- HPE Alletra Storage MP B10000 offers AI-managed, self-service unified storage with a disaggregated, scaleable architecture. It also ensures unmatched protection from downtime and ransomware threats.
If you need some assistance with analysis, design, and support for your storage solution, we also offer services to help you modernize, migrate, and protect your data storage. We’ll help you with every step of replacing your legacy systems with cohesive storage solutions.