What’s the Diff: NAS vs. SAN

The terms NAS and SAN can be confusing—the technology is similar and, making matters worse, the acronyms are the reverse of each other. NAS stands for network attached storage and SAN stands for storage area network. They were both developed to solve the problem of making stored data available to many users at once. But, they couldn’t be more different in how they achieve that goal.

The TL/DR:

• NAS is a single storage device that serves files over ethernet and is relatively inexpensive. NAS devices are easier for a home user or small business to set up.
• A SAN is a tightly coupled network of multiple devices that is more expensive and complex to set up and manage. A SAN is better suited for larger businesses and requires administration by IT staff. 

Read on and we’ll dissect the nuances of NAS and SANs to help you make informed decisions about which solution best suits your storage needs.

Basic Definitions: What Is NAS?

NAS is a device or devices with a large data storage capacity that provides file-based data storage services to other devices on a network. Usually, they also have a client or web portal interface that’s easy to navigate, as well as services like QNAP’s Hybrid Backup Sync or Synology’s Hyper Backup to help manage your files. In other words, NAS is synonymous with user-friendly file sharing. 

At its core, NAS operates as a standalone device connected to a network, offering shared access to files and folders. NAS volumes appear to the user as network-mounted volumes. The files to be served are typically contained on one or more hard drives in the system, often arranged in RAID arrays. Generally, the more drive bays available within the NAS, the larger and more flexible storage options you have.

Key Characteristics of NAS:

• File-Level Access: NAS provides file-level access, ideal for environments where collaborative work and content sharing are paramount.
• Simplicity: NAS solutions offer straightforward setups and intuitive interfaces, making them accessible to users with varying levels of technical expertise.
• Scalability: While NAS devices can be expanded by adding more drives, there may be limitations in terms of performance and scalability for large-scale enterprise use.

How NAS Works

The NAS device itself is a network node—much like computers and other TCP/IP devices, all of which maintain their own IP address—and the NAS file service uses the ethernet network to send and receive files. This system employs protocols like network file system (NFS) and server message block (SMB), enabling seamless data exchange between multiple users.

Benefits of NAS

NAS devices are designed to be easy to manage, making them a popular choice for home users, small businesses, and departments seeking straightforward centralized storage. They offer an easy way for multiple users in multiple locations to access data, which is valuable when users are collaborating on projects or need to share information. 

For individual home users, if you’re currently using external hard drives or direct attached storage, which can be vulnerable to drive failure, upgrading to a NAS ensures your data is better protected.  

For small business or departments, installing NAS is typically driven by the desire to share files locally and remotely, have files available 24/7, achieve data redundancy, have the ability to replace and upgrade hard drives in the system, and most importantly, support integrations with cloud storage that provide a location for necessary automatic data backups.

NAS offers robust access controls and security mechanisms to facilitate collaborative efforts. Moreover, it empowers non-technical individuals to oversee and manage data access through an embedded web server. Its built-in redundancy, often achieved through RAID configurations, ensures solid data resilience. This technology merges multiple drives into a cohesive unit, mimicking a single, expansive volume capable of withstanding the failure of a subset of its constituent drives.

Summary of NAS Benefits:

• Relatively inexpensive.
• A self-contained solution.
• Easy administration.
• Remote data availability and 24/7 access.
• Wide array of systems and sizes to choose from.
• Drive failure-tolerant storage volumes.
• Automatic backups to other devices and the cloud.

Limitations of NAS

The weaknesses of NAS primarily revolve around scalability and performance. If more users need access, the server might struggle to keep pace. If you overprovisioned your NAS, you may be able to add storage. But sooner or later you’ll need to upgrade to a more powerful system with a bigger on-board processor, more memory, and faster and larger network connections. 

Another drawback ties back to ethernet’s inherent nature. Ethernet divides data into packets, forwarding them to their destination. Yet, depending on network traffic or other issues, potential delays or disorder in packet transmission can hinder file availability until all packets arrive and are put back in order. 

Although minor latency (slowness) is not usually noticed by users for small files, in data-intensive domains like video production, where large files are at play, even milliseconds of latency can disrupt operations, particularly video editing workflows.

Basic Definitions: What Is a SAN?

On the other end of the spectrum, SANs are engineered for high-performance and mission-critical applications. They function by connecting multiple storage devices, such as disk arrays or tape libraries, to a dedicated network that is separate from the main local area network (LAN). This isolation ensures that storage traffic doesn’t interfere with regular network traffic, leading to optimized performance and data availability.

Unlike NAS, a SAN operates at the block level, allowing servers to access storage blocks directly. This architecture is optimized for data-intensive tasks like database management and virtualization or video editing, where low latency and consistent high-speed access are essential.

Key Characteristics of SANs:

• Block-Level Access: SANs provide direct access to storage blocks, which is advantageous for applications requiring fast, low-latency data retrieval.
• Performance: SANs are designed to meet the rigorous demands of enterprise-level applications, ensuring reliable and high-speed data access.
• Scalability: SANs offer greater scalability by connecting multiple storage devices, making them suitable for businesses with expanding storage needs.

How Does a SAN Work?

A SAN is built from a combination of servers and storage over a high speed, low latency interconnect that allows direct Fibre Channel (FC) connections from the client to the storage volume to provide the fastest possible performance. The SAN may also require a separate, private ethernet network between the server and clients to keep the file request traffic out of the FC network for even more performance. 

By joining together the clients, SAN server, and storage on a FC network, the SAN volumes appear and perform as if it were a directly connected hard drive. Storage traffic over FC avoids the TCP/IP packetization and latency issues, as well as any LAN congestion, ensuring the highest access speed available for media and mission critical stored data.

Benefits of a SAN

Because it’s considerably more complex and expensive than NAS, a SAN is typically used by businesses versus individuals and typically requires administration by an IT staff. 

The primary strength of a SAN is that it allows simultaneous shared access to shared storage that becomes faster with the addition of storage controllers. SANs are optimized for data-intensive applications. For example, hundreds of video editors can simultaneously access tens of GB per second of storage simultaneously without straining the network. 

SANs can be easily expanded by adding more storage devices, making them suitable for growing storage needs. Storage resources can be efficiently managed and allocated from a central location. SANs also typically include redundancy and fault tolerance mechanisms to ensure data integrity and availability.

Summary of a SAN’s Benefits:

• Extremely fast data access with low latency.
• Relieves stress on a local area network.
• Can be scaled up to the limits of the interconnect.
• Operating system level (“native”) access to files.
• Often the only solution for demanding applications requiring concurrent shared access.

Limitations of a SAN

The challenge of a SAN can be summed up in its cost and administration requirements—having to dedicate and maintain both a separate ethernet network for metadata file requests and implement a FC network can be a considerable investment. That being said, a SAN is often the only way to provide very fast data access for a large number of users that also can scale to supporting hundreds of users at the same time.

The Main Differences Between NAS and SANs

	NAS	SAN
Use case	Often used in homes and small to medium sized businesses.	Often used in professional and enterprise environments.
Cost	Less expensive.	More expensive.
Ease of administration	Easier to manage.	Requires more IT administration.
How data is accessed	Data accessed as if it were a network-attached drive.	Servers access data as if it were a local hard drive.
Speed	Speed is dependent on local TCP/IP ethernet network, typically 1GbE to 10GbE but can be up to 25GbE or even 40GbE connections, and affected by the number of other users accessing the storage at the same time. Generally slower throughput and higher latency due to the nature of ethernet packetization, waiting for the file server, and latency in general.	High speed using Fibre Channel, most commonly available in 16 Gb/s to 32 Gb/s however newer standards can go up to 128 Gb/s. FC can be delivered via high speed ethernet such as 10Gbit or 40Gbit+ networks using protocols such as FCoE and iSCSI.
Network connection	SMB/CIFS, NFS, SFTP, and WebDAV.	Fibre Channel, iSCSI, FCoE.
Scalability	Lower-end not highly scalable; high-end NAS scale to petabytes using clusters or scale-out nodes.	Can add more storage controllers, or expanded storage arrays allowing SAN admins to scale performance, storage, or both.
Networking method	Simply connects to your existing ethernet network.	Simply connects to your existing ethernet network.
Simply connects to your existing ethernet network.	Entry level systems often have a single point of failure, e.g. power supply.	Fault tolerant network and systems with redundant functionality.
Limitations	Subject to general ethernet issues.	Behavior is more predictable in controlled, dedicated environments.

Choosing the Right Solution

When considering a NAS device or a SAN, you might find it helpful to think of it this way: NAS is simple to set up, easy to administer, and great for general purpose applications. Meanwhile, a SAN can be more challenging to set up and administer, but it’s often the only way to make shared storage available for mission critical and high performance applications.

The choice between a NAS device and a SAN hinges on understanding your unique storage requirements and workloads. NAS is an excellent choice for environments prioritizing collaborative sharing and simple management. In contrast, a SAN shines when performance and scalability are top priorities, particularly for businesses dealing with data-heavy applications.

Ultimately, the decision should factor in aspects such as budget, anticipated growth, workload demands, and the expertise of your IT team. Striking the right balance between ease of use, performance, and scalability will help ensure your chosen storage solution aligns seamlessly with your goals.

Are You Using NAS, a SAN, or Both?

If you are using a NAS device or a SAN, we’d love to hear from you about what you’re using and how you’re using them in the comments.

NAS vs. SAN FAQs