NAS vs SAN – What is the Difference?

What Is the Difference Between a NAS and a SAN?

NAS (network-attached storage) and SAN (Storage Area Network) both allow users to share data among multiple devices and users at once. However, their approach to delivering data is quite different, and each has very different applications.

NAS devices serve files over Ethernet and are relatively inexpensive and easy to set up, while SANs are more expensive and complex to set up. As far as the user experience is concerned, the biggest difference between NAS and SAN is how they deliver shared storage. NAS devices deliver storage as network-mounted volumes and use protocols like NFS and SMB/CIFS, while SAN devices appear as local drives to the user and work on iSCSI or the more expensive Fiber Channel protocol.

This post aims to help you make an informed decision about whether NAS or SAN is best for your needs. We compare their strengths and weaknesses, as well as the types of applications they are most suitable for.

The Basics of NAS: What Is It?

A NAS provides client devices with file-based data storage. A NAS system usually consists of one or more hard drives that are often arranged in RAID arrays for redundancy.

By utilizing redundant data structures – often RAID – the NAS array allows multiple drives to appear as a single, large volume that can survive failures of a few drives.

NAS devices act as network nodes, each having its own IP address, and file transfers are performed via an Ethernet network. Users can see NAS volumes as network-mounted volumes.

Users can access data easily through NAS devices from different locations, making it ideal for project collaboration and sharing information. An onboard web server with a simple console provides good access control and security to facilitate collaboration and easy administration and data management without needing special staff.

However, a NAS is not designed to be a general-purpose server, but NAS vendors are increasingly offering server-like applications for NAS devices.

The Advantages of NAS

NAS allows users to share files locally and remotely, have files available 24/7, achieve data redundancy, replace and upgrade storage for scalability, and support integration with cloud storage for automatic data backups.

In Summary, NAS storage:

  • Is Cost-effective.
  • Provides Remote data access and 24/7 availability.
  • Has Fault-tolerant storage volumes.
  • Offers Administrative simplicity.

Limitations of NAS

In terms of scaling and performance, NAS is generally not a viable choice. When the number of requests from multiple users increases, there is a possibility that the server may not be able to keep up. The storage may be expanded and scaled up at this point. However, the system will also need to be overhauled with a more powerful onboard processor, more RAM, and faster network connections.

Eventually, there will come the point where either the storage cannot be further scaled up, or the hardware cannot be further upgraded or both. However, vendors like StoneFly offer (Super scale out) SSO NAS that can scale out indefinitely when performance increase is needed as much as the storage upgrade.

Ethernet itself is another problem. Ethernet transfers data by splitting it into segments called packets. There is the possibility that those packets can be delayed or sent out of order due to network congestion. This means that the user won’t be able to access the file until all the packets arrive and are reordered.

Users do not usually notice latency for small files, but it can be problematic in demanding environments like video production, where files can be huge. A latency of more than a few milliseconds can disrupt video editing.

The Basics of SAN: What is It?

A SAN is a block-based storage solution that connects servers to logical disk units (LUNs) provisioned from a pool of shared storage using a high-speed architecture – mostly iSCSI, FCP, or FCoE. SAN volumes behave and look like directly connected hard drives.

In addition, the server and clients may also use a private Ethernet network to keep metafile data requests out of the Fibre Channel network for even more performance.

SANs can reduce single points of failure and are highly reliable and resilient. Thus organizations use SAN to implement data security, data protection, and disaster recovery methodologies.

The Advantages of SAN

SAN is a flexible way to provide shared storage for several users in demanding applications such as video editing, database management systems and large virtualization environments. Businesses that need high throughput and low latency depend on storage area networks (SANs) to support business-critical applications. Using Fibre Channel, media and mission-critical data can be accessed at the fastest possible speeds while avoiding the packetization and latency issues associated with TCP/IP.

SAN’s low latency and high speed make it ideal for enterprise applications. By adding storage controllers to SAN, simultaneous shared access to storage becomes faster. It is possible to use hundreds of GB/s of storage at the same time. SANs are widely used in collaborative video production environments because of this reason.

But due to its complexity and price, SAN is typically reserved for large corporations and requires IT personnel to manage and maintain the systems.

In summary, SAN benefits from low latency, extremely fast data access, and lower network stress. SAN is usually the only solution for demanding applications requiring concurrent access.

Differences Between NAS and SAN:



Most suitable for small and medium businesses.

Best suited for large enterprises.

Less expensive.

More expensive.

Easier to manage and requires no administration or previous IT knowledge.

Requires more administration and technical staff.

Storage appears as a network-mounted volume.

Servers can access data as if they were local hard drives.

Speed depends on local TCP/IP, usually Ethernet network, typically 100 megabits to one gigabit per second. Generally, offers slower throughput and higher latency due to the slower file system layer. Speed is dependent on the speed of the Ethernet. SSO NAS can scale out to make up for that.

Uses a high-speed Fibre channel. Some SANs use comparatively slow but inexpensive iSCSI as an alternative to the fibre channel.



Not suitable for large virtualization environments.

Best suited to large enterprise virtualization environments with multiple VMs.

Requires almost no structural changes to the infrastructure.

Requires architectural changes.

Performance can degrade with network congestion.

Does not bottleneck.

NAS and SAN Use Cases:

NAS Use Cases:

A general-purpose file storage and sharing service: In mid-sized, small and medium-sized businesses, and enterprises, this is one of NAS’s major uses. With a SSO NAS device, IT can consolidate multiple file servers, simplify management, and save space and time.

Big data applications: SSO NAS is ideal for processing large files, performing ETL, and monitoring and analyzing data. NAS can also store large amounts of unstructured data, such as video surveillance and streaming.

Virtualization: Virtualization can work on NAS, but not everyone is sold on the idea. This is a growing trend; VMware and Hyper-V both support NAS data stores. It is a popular choice for small or new virtualization environments without a SAN.

Active archives: Cold storage or tape storage are the best options for long-term archiving. However, NAS is a good choice for searchable, accessible active archives. In addition to being searchable and accessible, NAS can also replace large tape libraries.

SAN Use Cases:

Applications requiring high performance and business-criticality commonly use storage area networks, for instance:

Database Management Systems: These are Business-critical applications that require high availability and performance. For instance, Oracle and the Microsoft SQL Server database store the most valuable data of an enterprise, so their performance and availability must be the highest.

Large virtualization deployments: Large Virtualization deployments using VMware, KVM, or Microsoft Hyper-V are the best use case for SAN. These environments may have thousands of virtual machines running different operating systems and applications, each with its own performance requirements. The complexity of virtualized environments makes infrastructure reliability even more important since a failure can affect multiple applications at once. NAS devices can also support virtualization, but iSCSI SANs are more suitable for large-scale and high-performance deployments. In addition to facilitating multiple I/O streams between VMs and the virtualization host, the storage area network provides high scalability to allow dynamic data processing.

Large virtual desktop infrastructures (VDIs): Virtual desktop environments serve large numbers of users within an organization. It is not uncommon for VDI environments to have tens of thousands of virtual desktops. Organizations can more easily manage security and data protection by centralizing virtual desktops.

SAP, ERP or CRM environments: E-commerce and customer resources management workloads are also ideal for SAN architectures.

Video editing: Video editing applications require low latency and high data transfer rates. SANs provide this high performance because they can connect directly to the desktop client, dispensing with the extra layer of the server.

NAS and SAN – Coming Together

Many vendors are offering SAN products at lower costs that have all the benefits of a SAN by avoiding the high cost of Fibre Channel. For example, FCoE (Fiber Channel over Ethernet) can deal with block-level transfers with speeds up to 10GB/sec. The cost of StoneFly iSCSI SAN is even lower as it allows SCSI commands to be sent inside IP packets over the Ethernet. Thus this partial convergence of NAS and SAN has brought SAN storage at a lower cost than the FC (Fibre Channel) SAN.

Bottom Line

The choice between SSO NAS and SAN solution will ultimately boil down to several factors, including your capacity and budget needs. If you have an existing environment that has been built up for years, a migration to either solution might not be feasible. However, if you are in the early stages of planning your storage strategy and want to get in on the latest advancements in enterprise storage, it may be worth evaluating both NAS and SAN.

SANs generally provide a higher level of availability, reliability and performance than NAS, but they cost more and are difficult to manage. NAS systems are easy to deploy and maintain and are suitable for SMBs and SMEs. As always, there is no perfect solution, and you should evaluate your requirements.

Most businesses deal with their storage and networking requirements by implementing a combination of NAS and SAN to meet their unique needs. The choice is up to you, but be sure you understand the differences between the two before deciding which will meet your company’s needs best.

Author Bio:

George Williams, Senior Technical & Product Marketing Specialist, StoneFly Inc.

George Williams has over 13 years of experience in the data storage, backup and disaster recovery, air-gapping, immutability and archiving markets. A true geek with love for ease and simplicity in data storage, George has been working for StoneFly Inc. for over a decade. Ever since StoneFly started shipping products since 2006, George has been working to ensure that technical information is relayed in a simple and effective way to customers and targeted audience. George helps curate content and works with numerous publishers and technology blogs to spread awareness and knowledge of data storage technology.

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