NAS vs SAN: What’s the Difference?

Network-attached storage (NAS) and storage area networks (SAN) are two methods of configuring storage devices over a network to help business users share data wherever they’re connected to the network. Both NAS and SAN provide a fast, cost-effective way for organizations to support large volumes of stored data, but they approach this differently and are often suited to different applications. They’re beneficial for exchanging files and data among remote teams, which is essential for most businesses. This guide defines NAS and SAN, identifies their differences, and presents use cases for both architectures.

Jump to:

• NAS vs SAN Comparison Chart
• How Do NAS and SAN Work?
• Main Similarities Between NAS and SAN
• When to Use NAS and SAN
• Bottom Line: NAS and SAN Aren’t Opposites

NAS vs SAN: Comparison Chart

The following table highlights some of the key differences between NAS and SAN environments.

	NAS	SAN
Fabric	TCP/IP networks, most commonly Ethernet	Fibre Channel or IP-based fabric
Data processing	Processes file-based data May operate within a global namespace, aggregating multiple NAS file systems to present a consolidated view	Processes block-based data Accesses specialized SAN file system; servers share data by providing file-level access to servers on the same Logical Unit Number
Protocols	Ethernet NFS SMB/CIFS HTTP	Uses SCSI protocol to communicate with servers Network formed by mapping layers to other protocols like Fibre Channel Protocol (FCP) Potential for NVMe fabric
Performance	Lower throughput and higher latency High-speed networks that can make up for performance losses within NAS  Higher processing capabilities necessary for performing bandwidth-intensive tasks	Typically higher-performing in environments like high transaction databases and e-commerce websites Technologies like Fibre Channel and NVMe help process traffic requests
Scalability	Entry-level and NAS devices aren’t highly scalable High-end NAS systems scale to petabytes	Scalability is a major driver for purchasing a SAN Network architecture enables admins to scale performance and capacity
Price	Generally less expensive to purchase and maintain Fewer hardware and software components	Generally higher administrative costs  Also have security features, which cost more money to implement and maintain
Ease of management	Easily plugs into LAN Offers a simplified management interface	Requires more administration time than NAS devices Deployment often requires making physical changes to the data center Typically requires specialized admins

How do NAS and SAN Work?

While NAS and SAN technologies both allow teams to share data remotely over a network, they’re set up differently and vary in transfer speed.

How Network Attached Storage Works

NAS is a file-level data storage device attached to a TCP/IP network, usually Ethernet. It typically uses Network File System (NFS) or Common Internet File System (CIFS) protocols, although other choices like HTTP are available. The device contains a number of replaceable drives—either solid state drives or hard drives—as well as a processor and often a built-in operating system. NAS devices may provide other features, too, like integrations with backup software or creative tools.

NAS appears to users as a shared folder. Employees access files from the NAS like they do any other file on the network. NAS is dependent on the local area network to which it’s connected. If the LAN goes down, so does the NAS.

NAS is not typically as fast as storage area networks because SANs are block-based storage. Blocks are typically read more quickly than files on a storage device and are typically better suited to high-performance applications. However, high-speed LANs can overcome most performance and latency issues.

How a Storage Area Network Works

While NAS is a storage device connected to an existing LAN, SAN is a dedicated high-performance network for consolidated block-level storage. The network fabric of a SAN interconnects storage devices, switches, hosts, and all the other hardware that comprises the network. High-end enterprise SANs may also include SAN directors for higher performance and efficient capacity usage. Because a SAN is a standalone network, it isn’t dependent on another business network to transfer data.

Servers connect to the SAN fabric using host bus adapters (HBAs). Servers identify the SAN as locally attached storage, so multiple servers can share a storage pool. SANs are not dependent on the LAN and relieve pressure on the local network by offloading data directly from attached servers.

Common SAN protocols include Fibre Channel, internet small computer systems interface (iSCSI), and non-volatile memory express over Fibre Channel (NVMe over FC). Businesses use these protocols to transfer data between users on a network.

Two Main Similarities Between NAS and SANs

NAS and SAN solutions often support different storage applications and serve different needs, but they have similarities as well, including network-based storage and support for virtualization technology.

Network-based

Sharing data across a network expands businesses’ storage options—both NAS and SAN environments are helpful for remote teams, because they allow geographically disparate employees to share files and use company data.

Virtualization support

NAS and SAN both support virtualization technologies like hypervisors and virtual machines. If you have high-performance needs, look to storage area networks, but some enterprise-level NAS devices integrate with virtualization products.

When to Use NAS and SAN

NAS and SAN each serve specific use cases well. They’re also not mutually exclusive—businesses may use both NAS and SAN solutions depending on their storage infrastructure and applications.

Use Cases for Network Attached Storage

Depending on your team’s top priorities, look for NAS solutions that support these storage needs.

File storage and sharing

This is the major NAS use case in mid-sized, SMB, and enterprise remote offices. A single NAS device allows IT to consolidate multiple file servers for simplicity, ease of management, and space and energy savings.

Active archives

Long-term archives are best stored on less expensive storage like tape or cloud-based cold storage. NAS is a good choice for searchable and accessible active archives, and high-capacity NAS can replace large tape libraries for archives.

Big data

Businesses have several choices for big data: scale-out NAS, distributed JBOD (Just a Bunch of Disks) nodes, all-flash arrays, and object-based storage. Scale-out NAS is good for processing large files, ETL (extract, transform, load), intelligent data services like automated tiering, and analytics. NAS is also a good choice for large unstructured data such as video surveillance and streaming, and post-production storage.

Virtualization

Not everyone is sold on using NAS for virtualization networks, but usage is growing—and VMware and Hyper-V both support their datastores on NAS. This is a popular choice for new or small virtualization environments when the business does not already own a SAN. NAS provider Synology even has its own hypervisor software, called Synology Virtual Machine Manager, and supports VMware vSphere and Microsoft Hyper-V machines.

Virtual desktop interface (VDI)

Mid-range and high-end NAS systems offer native data management features that support VDI, such as fast desktop cloning and data deduplication. VDI is also useful for enterprises that have multiple remote sites, since it uses the remote desktop protocol (RDP) to connect devices.

Is your business considering a NAS? Read about top enterprise NAS devices next. 

Use Cases for Storage Area Networks

When your business is considering implementing a SAN, analyze products and protocols to see whether they meet your organization’s needs. SANs typically support the following applications and use cases.

Databases and e-commerce websites

General file serving or NAS will do for smaller databases, but high-speed transactional environments need the SAN’s high input/output (I/O) processing speeds and very low latency. This makes SANs a good fit for enterprise databases and high-traffic e-commerce websites.

Fast backup

Server operating systems view the SAN as attached storage, which enables fast backup to the SAN. Backup traffic does not travel over the LAN since the server is backing up directly to the SAN. This makes for faster backup without increasing the load on the Ethernet network. Appliances on the SAN that use NVMe for backup or recovery, for example, may speed the process as well.

Virtualization

NAS supports virtualized environments, but SANs are better suited to large-scale and/or high-performance deployments. The storage area network quickly transfers multiple I/O streams between VMs and the virtualization host, and high scalability enables dynamic processing.

Video editing

Video editing applications need very low latency and very high data transfer rates. SANs provide this high performance because it cables directly to the video editing desktop client, dispensing with an extra server layer. Video editing environments need a third-party SAN distributed file system and per-node load balancing control.

Streaming

Enterprises that regularly stream data on high-performance applications, whether that’s video or just dynamic fields on customer-facing apps, require a SAN’s high data transfer rates as well.

Read about the best SANs for businesses next.

Bottom Line: NAS and SAN aren’t Opposites

NAS versus SAN doesn’t tell the whole story when comparing these two popular storage architectures. NAS and SAN are as complementary as they are competitive—they fill different needs in enterprise storage environments. Many larger organizations own and use both in a wide range of applications.

However, enterprise IT budgets are not infinite, and organizations need to optimize their storage expenditures to suit their priority requirements. Determine which type of storage environment you need and the applications you’re supporting, and select a solution based on that.

Learn how to secure your business’ NAS environment next.