What is NAS (Network-Attached Storage)?

Enterprise and small businesses in many industries choose NAS solutions because they offer effective, scalable, and low-cost storage. Compared to other servers, NAS file servers give faster data access and are easier to configure and manage. They can support various business applications, including private email systems, accounting databases, payroll, video recording and editing, data logging, and business analytics.

Some benefits of NAS include:

Private cloud deployment for organizations

A private cloud is a cloud that hosts resources from an organization’s own data center. It can be based on internal hardware resources or separate infrastructure provided by a third party. You can use NAS appliances to deploy private cloud storage in your organization.

Flexible local storage solutions for small businesses

NAS systems can be customized based on the size and requirements of the organization. Both low-cost, less storage, and more expensive high-end devices are available in the market.

NAS devices are typically made up of several components.

Physical storage drives

NAS devices can contain from two to five hard drives, which gives them high-volume storage capacity. Multiple physical drives are arranged logically as redundant storage containers (RAID). RAID is a virtualization technology that combines multiple physical storage components into one or more logical units. This helps back up data and improve performance.

Central processing unit (CPU)

NAS devices have a CPU that provides computing intelligence and power to manage the file system. The CPU reads and writes data to process and serve files, manage multiple users, and integrate with the cloud if desired.

Operating system

An operating system is a software interface between the storage device hardware and its user.. Although complex network-attached storage devices come with their own operating systems, some simpler devices may not have one.

Networking interface

The NAS unit connects to the network by using the networking interface. The network connection can be an ethernet cable or Wi-Fi. Many NAS devices also have USB ports for charging or to connect other devices to the NAS device.

NAS systems combine hardware and software with protocols (or rules) to support file sharing over the network. By following these protocols, any computer can seamlessly access files from the NAS device as if the files were stored on the computer itself.

Communication protocols

Networks can run multiple data transfer protocols, but most networks have internet protocol (IP) and transmission control protocol (TCP). IP is the part that obtains the address to send file data. After that, TCP delivers the data by combining it into packets and sending the packets through the network.

File formatting protocols

Machines in a computer network can have different underlying operating systems, like Windows, Linux, or Unix. All of them want to access the NAS file storage in their native file format. Therefore, NAS file systems format the data before sending it to the network. The formatting protocols for file serving include:

Network File Systems (NFS)

Linux and UNIX systems use this protocol. NFS works on any hardware, OS, or network architecture.

Server Message Blocks (SMB)

Microsoft Windows machines use this protocol.

Apple Filing Protocol (AFP)

This is a proprietary protocol for Apple devices running macOS.

NAS is one among other network storage solutions.

Storage area networks

A storage area network (SAN) is a dedicated high-speed network that interconnects multiple servers with a vast range of storage devices. Organization use SAN to centrally access, replicate, and protect all their storage as a single collective resource. SAN also uses additional technologies, such as RAID and data deduplication to optimize storage capacity and reliability.

NAS vs. SAN

Both NAS and SAN are networked storage systems. They pool storage capacity and share it with application servers over a high-speed network. The main difference between them is how the user perceives them. To clients, NAS works as a file system and SAN works as the operating system. NAS handles individual file requests, but SAN manages requests for contiguous blocks of data. NAS and SAN also use different underlying protocols and technologies. SAN is more flexible for users, but it can cost more to set up and manage. 

Direct-attached storage

Direct-attached storage (DAS) is storage that can be directly attached to a server device. The most common example of DAS is a cable-connected external hard drive. Only the host server can access the data directly. Other devices have to request data from the host device.

NAS vs. DAS

DAS is the precursor to NAS. DAS attaches directly to servers so the expansion slots in the server constrain both its scale and connectivity. DAS size also restricts storage capacity, and limits it to a small number of ports or host connections. It does not lend itself well to sharing and is complex to manage.

You can overcome NAS limitations by adding more NAS devices to the network, integrating with SAN, or replacing NAS devices with cloud storage. Let's explore the options below:

To increase storage capacity, you can either scale up or scale out NAS architecture. Scaling up means using storage controller software to manage multiple physical drives on the same NAS server. Scaling out means using a common software communication interface called API to manage multiple NAS servers. By scaling out, organizations can make space for billions of files. However, it is costly to configure, code, and manage.

Despite their differences, SAN and NAS are not mutually exclusive. You can combine them to form a SAN-NAS hybrid, which gives you both file-level and block-level protocols from the same system. You can also run NAS on top of a SAN system to get filesystem services. You can find devices with hybrid SAN/NAS components in the market.

You can augment or replace physical NAS by using cloud-based file storage. A cloud gateway at the edge of a company's data center network moves application data between local storage and the public cloud. A cloud provider manages and operates the data storage as a service. You can access storage on demand with just-in-time capacity and costs, eliminating the need to buy and manage your own data storage infrastructure. Cloud storage gives you agility, global scale, and durability with any time, anywhere data access.