What is a NAS Server? A Comprehensive Guide to Network-Attached Storage

In today’s data-driven world, efficient and accessible storage solutions are paramount for both individuals and businesses. Network-attached storage (NAS) stands out as a versatile and cost-effective solution for centralized file storage, enabling multiple users and diverse client devices to retrieve data from a shared disk capacity. Connected to a local area network (LAN) via a standard Ethernet connection, a NAS server simplifies data access and management, making it an increasingly popular choice for various storage needs.

Unlike traditional servers, NAS devices are purpose-built for storage and typically operate without a keyboard or display. Configuration and management are streamlined through a user-friendly, browser-based utility. Each NAS device functions as an independent node on the network, identified by its unique IP address, ensuring seamless integration into existing network infrastructures.

Network attached storage mobile

The appeal of NAS lies in its ease of use, substantial storage capacity, and affordability. It serves as a central repository for data consolidation, offering support for cloud integration and essential tasks like data archiving and backup. This makes NAS a robust solution for managing growing data volumes and ensuring data protection.

Network-attached storage and storage area networks (SANs) represent the two primary types of networked storage architectures. NAS excels in handling unstructured data, which encompasses a wide range of file types such as audio, video, website content, text documents, and Microsoft Office files. Conversely, SANs are primarily engineered for block storage, which is crucial for structured data within databases and enterprise applications. Understanding this fundamental difference is key to choosing the right storage solution for specific needs.

What are the Common Uses of Network-Attached Storage?

The core purpose of network-attached storage is to facilitate efficient data sharing and collaboration, particularly for teams that are geographically dispersed or operating across different time zones. By connecting to a wireless router, a NAS server enables remote access to files from virtually any network-connected device, be it a desktop computer or a mobile device. This accessibility makes NAS invaluable for enhancing productivity and streamlining workflows in distributed work environments.

Organizations frequently utilize NAS as a storage filer, effectively centralizing file storage and access. It also serves as a foundational element for building personal or private clouds, providing users with greater control over their data and enhanced privacy compared to public cloud services.

NAS solutions are available in a spectrum of configurations, catering to diverse needs ranging from large enterprises to home offices and small businesses. While basic NAS devices may feature single drive bays for non-critical data, most units come equipped with at least two bays to support redundancy and increased capacity. Enterprise-grade NAS systems, designed for more demanding environments, typically include four or more drive bays and incorporate advanced data management features to optimize storage efficiency and reliability.

Before the widespread adoption of NAS, enterprises often grappled with the complexity of managing numerous file servers. NAS appliances simplify storage expansion through a scale-up approach, where capacity is increased by adding larger or more disk drives. For even greater scalability, NAS appliances can be clustered together to create scale-out storage architectures, accommodating massive data growth and high-demand environments.

Furthermore, many NAS vendors have established partnerships with cloud storage providers, offering users the advantage of redundant backup and hybrid cloud strategies. This integration provides an extra layer of data protection and flexibility in managing storage resources.

While NAS excels at facilitating collaboration, it’s important to consider potential performance bottlenecks. Traditional NAS systems relying on hard disk drives (HDDs) can experience I/O contention when numerous users simultaneously access the system. To address this, modern NAS systems are increasingly incorporating faster solid-state drives (SSDs) or flash storage, either as a dedicated tier alongside HDDs or in all-flash configurations. These advancements significantly improve performance, especially for applications requiring rapid data access.

Network attached storage mobile

NAS Use Cases and Practical Examples

The selection of hard disk drive (HDD) type for a NAS device is largely dictated by its intended applications. For routine tasks like sharing Microsoft Excel spreadsheets or Word documents, or performing periodic data backups, standard HDDs may suffice. However, applications that involve handling large streaming media files demand higher-capacity disks, increased memory, and more robust network processing capabilities.

In home environments, NAS systems are commonly used for storing and serving multimedia content and automating data backups. Home users leverage network-attached storage for a variety of purposes, including:

• Smart TV Storage Management: Expanding storage capacity for smart TVs to accommodate large media libraries.
• Security System Management: Storing video footage from home security cameras and managing security system updates.
• Consumer IoT Device Management: Centralizing data from various consumer-based Internet of Things (IoT) devices.
• Personal Media Streaming Service: Creating a home-based media server to stream movies, music, and photos across devices.
• Torrent File Management: Efficiently downloading and managing torrent files.
• Personal Cloud Server Hosting: Establishing a personal cloud for file sharing and access outside the home network.
• Personal Website Development and Testing: Hosting and testing personal websites in a secure and controlled environment.

In enterprise settings, NAS plays a critical role in numerous applications, such as:

• Backup Target for Archiving and Disaster Recovery: Serving as a reliable backup repository for critical data, facilitating archiving and disaster recovery strategies.
• Web Application Testing and Development: Providing a platform for testing and developing web-based and server-side web applications.
• Messaging Application Hosting: Hosting email servers and other messaging applications.
• Server-Based Open Source Application Hosting: Hosting open-source applications like customer relationship management (CRM), human resource management (HRM), and enterprise resource planning (ERP) systems.
• Serving Diverse File Types: Delivering email, multimedia files, databases, and print jobs to users across the network.

Consider the scenario of an enterprise that processes a large volume of images daily. Cloud-based streaming may be impractical due to latency issues. In such cases, an enterprise-class NAS becomes essential for storing images locally, while cloud caching can be employed to maintain efficient connections to on-premises data.

High-end NAS products often support redundant arrays of independent disks (RAID), a storage configuration that combines multiple hard disks into a single logical unit. RAID enhances performance, ensures high availability, and provides data redundancy, safeguarding against drive failures.

Components of a NAS Server and How They Operate

At its core, a NAS device is a specialized storage server, purpose-built to facilitate storage access over a network. Regardless of its scale, every NAS device typically comprises four essential components:

Netgear is one of several popular NAS vendors

• CPU (Central Processing Unit): The CPU is the brain of the NAS, working in conjunction with memory to execute the NAS operating system (OS), manage data read/write operations, handle user access requests, and integrate with cloud storage services if configured. While general-purpose CPUs are common in computers and servers, NAS devices may utilize specialized CPUs optimized for high performance and energy efficiency in storage-centric applications.
• Network Interface: While some smaller, desktop-oriented NAS devices may offer direct computer connections like USB or limited Wi-Fi, business-grade NAS designed for data sharing and file serving invariably require a physical network connection. This is typically achieved through a cabled Ethernet interface, assigning the NAS a unique IP address. The network interface is often considered an integral part of the NAS hardware suite, alongside the CPU.
• Storage: Physical storage is fundamental to any NAS device, typically provided by disk drives. These drives can be traditional magnetic HDDs, SSDs, or a combination of different storage media. NAS devices often support logical storage organization, such as mirroring and RAID implementations, to enhance redundancy and performance. However, it’s the CPU, not the disks themselves, that manages this logical organization.
• Operating System (OS): Similar to a conventional computer, the NAS OS is responsible for managing the NAS hardware and making storage resources accessible to clients, including users and applications. Simpler NAS devices may have less prominent operating systems, whereas more sophisticated systems may feature dedicated NAS operating systems like Netgear ReadyNAS, QNAP QTS, Zyxel FW, or TrueNAS Core.

Key Considerations for NAS Selection

Choosing the right NAS device involves more than just storage capacity. Enterprise NAS users must evaluate a range of factors beyond price to ensure optimal performance, reliability, and suitability for their specific needs.

• Capacity: Determining the required storage capacity is crucial. This involves considering both the number of disk bays and the logical disk organization. For instance, a NAS with two 4 TB drives could theoretically offer 8 TB of raw capacity. However, if configured in RAID 1 (mirroring), the usable capacity would be reduced to 4 TB to provide data redundancy.
• Form Factor: The physical installation environment dictates the appropriate form factor. Rackmount NAS units, typically 2U or 4U in size, are designed for data center racks. Tower or standalone NAS units are better suited for smaller departmental closets or desktop deployments.
• Performance: The anticipated number of concurrent users and the intensity of their storage demands directly influence performance requirements. A heavily utilized NAS needs sufficient network bandwidth and internal processing power to handle storage requests efficiently. Insufficient performance can lead to latency and degraded user experience.
• Connectivity: Network connectivity options are vital. Most NAS devices offer one or more Ethernet ports for wired network connections. High-bandwidth network connectivity is essential for enterprise data centers. Smaller deployments may suffice with Wi-Fi, while personal NAS devices might offer USB ports for direct PC connection.
• Reliability: NAS reliability encompasses device durability, disk reliability, and data integrity. The NAS device itself should be designed for continuous operation at peak loads. Disk reliability depends on the quality of installed drives, with high-quality SAS disks offering superior error correction and longer lifespans. Data reliability is often addressed through RAID, replication, and other data protection mechanisms that must be properly configured.
• Security: Robust security features are paramount. NAS devices should offer native data encryption and strong network access controls to restrict storage access to authorized users and applications.
• Usability and Features: Ease of setup and deployment are important usability aspects. Consider the features included in the NAS OS/software, such as data snapshots, backups, replication, automatic data tiering, and RAID management.

Why Choosing the Right NAS is Critical

Investing in network-attached storage represents a significant commitment of resources. The selected NAS will become a vital resource for users, whether in a home, small business, or large enterprise. Therefore, a thorough evaluation of the aforementioned considerations is essential before making a purchase decision. An unsuitable NAS choice can lead to several undesirable outcomes:

• Inadequate Storage Capacity: While NAS capacity can often be expanded, accurately predicting long-term storage needs is crucial. Overestimating capacity leads to wasted investment, while underestimation can result in storage shortages and the need for additional NAS purchases.
• Insufficient Performance: NAS performance must be sufficient to serve multiple clients across the network. Inadequate performance can cause application lag and a poor user experience.
• Lack of Resilience: Basic NAS setups may lack robust data protection. Businesses that rely on data availability and must guard against data loss due to drive failures need to implement resilience features like RAID. Failure to do so can expose the business to significant risks.
• Inadequate Security: Data security is a fundamental requirement for all businesses. NAS systems must provide adequate access control and security features like data encryption to meet security and compliance requirements. Deficiencies in these areas can increase business risks.

NAS Product Categories

NAS devices are broadly categorized into three segments based on drive count, drive support, capacity, and scalability:

High-End or Enterprise NAS

The high-end NAS market is driven by organizations with massive file data storage and sharing needs, including virtual machine (VM) images. Enterprise NAS systems can scale to petabytes of storage, serve thousands of clients, and offer high-speed access and clustering capabilities. Clustering addresses the single point of failure concern inherent in traditional NAS setups.

By distributing mission-critical applications and data across multiple NAS devices and implementing scheduled backups, redundancy is enhanced, minimizing risks. Redundancy is typically achieved through data duplication, where data is copied to multiple storage devices or subsystems.

Clustered NAS systems also help mitigate NAS sprawl. A distributed file system operates concurrently across multiple NAS devices, providing unified access to all files within the cluster, regardless of their physical location.

Midmarket NAS

Midmarket NAS solutions cater to businesses with hundreds of clients and storage needs in the range of hundreds of terabytes. While these devices offer substantial capacity, they typically lack clustering capabilities, which can lead to file system silos if multiple NAS units are deployed.

Low-End or Desktop NAS

Low-end NAS devices target home users and small businesses with modest shared storage needs for a few clients, typically up to several terabytes. This segment is increasingly shifting towards cloud NAS service models, with offerings like Buurst’s SoftNAS Cloud NAS and software-defined storage (SDS) solutions from established storage vendors.

Find out about the three basic types of NAS systems low-end midmarket and high-end NAS

NAS Deployment Strategies for Business

NAS deployments in business environments can be approached in various ways, each with its own advantages and disadvantages. These deployments are typically manageable by a single network administrator.

The common NAS deployment approaches include:

• NAS Gateways: Ideal for large, enterprise-class users who already have a SAN infrastructure.
• Integrated NAS: Suitable for users of all sizes who do not have a SAN.
• Clustered File Systems: Optimal for large compute cluster users requiring high-performance file data access.
• Parallel File Systems: Also well-suited for large compute cluster users needing high-performance file data access, or any organization requiring parallel access to file data.
• NAS Aggregators: Best for environments with multiple NAS devices from different vendors.

Learn about the pros and cons of various approaches to implementing NAS

NAS File-Sharing Protocols

The basic functionality of NAS devices has expanded to include virtualization support. High-end NAS products may also incorporate advanced features like data deduplication, flash storage integration, multiprotocol access, and data replication.

While some NAS devices run standard operating systems like Microsoft Windows, others utilize proprietary vendor OSs. IP is the most prevalent data transport protocol, but midmarket NAS products may also support protocols like:

• Network File System (NFS)
• Internetwork Packet Exchange (IPX)
• NetBIOS Extended User Interface (NetBEUI)
• Server Message Block (SMB)
• Common Internet File System (CIFS)

Furthermore, high-end NAS devices often support Gigabit Ethernet for faster network data transfer speeds.

Larger enterprises are increasingly adopting object storage for handling massive data volumes. However, NAS devices are expected to remain a valuable storage solution for small and medium-sized businesses due to their versatility and cost-effectiveness.

Scale-Up and Scale-Out NAS vs. Object Storage

Scale-up and scale-out represent two distinct NAS architectures, while object storage offers an alternative approach to managing unstructured data.

Scale-Up NAS

In a scale-up NAS architecture, the NAS head, which controls access to back-end storage via a network connection, is the central component. Capacity expansion is achieved by adding drive shelves to the controllers, limited by the scalability of the controllers themselves.

Scale-Out NAS

Scale-out systems offer greater scalability by allowing storage administrators to add larger NAS heads and more hard disks to increase storage capacity. This architecture provides the flexibility to adapt to evolving business needs and can accommodate billions of files without performance degradation during metadata searches.

Object Storage

Object storage is emerging as a potentially transformative technology, with some experts predicting it will eventually surpass scale-out NAS. However, it’s more likely that both technologies will coexist, serving different needs. While both address scalability, they do so in fundamentally different ways.

NAS file management relies on the Portable Operating System Interface (POSIX), ensuring data security and enabling multiple applications to share a scale-out device without data corruption.

Object storage, in contrast, is designed for web-scale environments requiring extreme scalability. It excels at managing unstructured data that is not easily compressible, particularly large video files. Object storage bypasses POSIX and traditional file systems, presenting all objects within a flat address space. Metadata tags are added to each object for efficient identification within this flat namespace.

NAS vs. DAS (Direct-Attached Storage)

Direct-attached storage (DAS) refers to storage directly connected to a server or computer without a network in between. A computer’s internal HDD is a basic example of DAS. Accessing DAS files requires physical access to the storage device.

DAS often offers superior performance compared to NAS, especially for compute-intensive applications, due to direct disk access and the absence of network latency. In its simplest form, DAS may just be the internal drives within a server.

However, DAS requires managing storage independently on each device, adding complexity. Unlike NAS, DAS is not well-suited for shared storage among multiple users.

NAS vs. SAN (Storage Area Network)

What distinguishes SAN from NAS? A SAN organizes storage resources on a dedicated, high-performance network. NAS handles file-level I/O requests, whereas a SAN manages block-level I/O requests.

NAS traffic typically traverses TCP/IP networks like Ethernet. SAN, on the other hand, often utilizes Fibre Channel (FC), a protocol specifically designed for storage networks. SANs can also employ the Ethernet-based iSCSI protocol as an alternative to FC.

While NAS can be a single device, SAN provides block-level access to server disk volumes. From a client OS perspective, NAS appears as a file system, while a SAN is perceived as a local disk.

SAN/NAS Convergence

Historically, file and block storage domains remained separate due to technological limitations, each with distinct management paradigms, strengths, and weaknesses. Block storage was often considered “first-class” for mission-critical databases housed on SANs, while file storage was deemed “economy class.”

Unified storage emerged to bridge this gap, aiming to enhance large-scale file storage through SAN/NAS convergence. This approach consolidates both block- and file-based data on a unified storage array, supporting both SAN block I/O and NAS file I/O within the same infrastructure.

The benefits of SAN/NAS convergence extend beyond mere storage consolidation. SAN and NAS are complementary technologies, and their integration offers numerous advantages:

• Elimination of isolated SAN and NAS storage silos, reducing complexity.
• Improved storage scalability and a unified management platform for both SAN and NAS.
• Enhanced file-level access and virtualization for SAN environments.
• Optimization for mixed file and block data workloads.
• Reduced costs associated with separate SAN/NAS infrastructure and management.

Hyper-converged infrastructure (HCI), pioneered by companies like Nutanix and SimpliVity (now part of HPE), emerged in 2014. HCI bundles computing, networking, SDS, and virtualization resources into a single appliance. HCI systems pool different storage media tiers and present them to a hypervisor as a NAS mount point, even though the underlying storage is block-based. However, HCI file services are often basic, potentially necessitating a separate network for advanced file storage needs.

Converged infrastructure (CI) packages servers, networking, storage, and virtualization on vendor-integrated and validated hardware, but uses separate devices instead of a single chassis like HCI. This offers greater architectural flexibility. Organizations seeking simplified storage management may consider CI or HCI to replace traditional NAS or SAN environments.

Modern convergence and HCI offerings not only combine SAN and NAS storage but also integrate computing (servers) and networking, optimizing data center deployment and build-out strategies.

NAS and File Storage Vendors

Despite the rise of flash storage, network-attached storage systems still predominantly rely on spinning media. A wide range of vendors offer NAS solutions, often providing multiple configurations to balance capacity and performance.

NAS systems are available both fully populated with disks and as diskless chassis, allowing customers to add their preferred HDDs. Drive vendors like Seagate and Western Digital collaborate with NAS providers to develop and qualify storage media.

Notable NAS appliance and scalable file storage vendors include:

• Accusys Storage Ltd.
• Arcserve Inc.
• Asustor
• Buffalo Americas Inc.
• Buurst Inc.
• Cloudian
• Ctera Networks
• Ciphertex Data Security
• DataDirect Networks
• DataOn Storage
• Dell EMC
• Drobo
• Excelero Inc.
• Fujitsu
• Hitachi Vantara
• HPE
• Huawei
• IBM
• Infinidat
• IXSystems Inc.
• Microsoft Azure
• NetApp Inc.
• Netgear
• Nexenta Systems Inc.
• Nexsan
• Oracle
• Panasas
• Pure Storage
• Quanta Cloud Technology
• QNAP Systems Inc.
• Quantum Corp.
• Qumulo Inc.
• Rackspace Technology
• Seagate
• Spectra Logic Corp.
• Synology Inc.
• TerraMaster
• Thecus Technology Corp.
• Verbatim Corp.
• WekaIO
• Western Digital Corp.
• Zadara Storage

Cloud-Based File Storage

In addition to physical NAS devices, cloud-based file storage is increasingly used to augment or replace on-premises NAS. Services like Amazon Elastic File System and Microsoft Azure Files offer scalable file shares accessible to both local and cloud deployments.

Cloud file storage aims to provide the same ease of use and convenience as local NAS, with use cases spanning web serving, content management, data analytics, backups, archiving, streaming, and software development. Cloud providers must ensure high availability, performance, security, comprehensive management, and cost-effectiveness.

Common cloud file storage options include:

• Barracuda Cloud Backup
• Dropbox
• Google Drive
• IDrive
• Microsoft OneDrive

NAS gateways, once used to access external storage, are less common today, with cloud storage gateways, object storage, and scale-out NAS being preferred alternatives. Cloud gateways facilitate application traffic between local storage and the public cloud. Companies like Nasuni and Panzura offer cloud-native file system software and services to enable seamless cloud integration.

The Future of Network-Attached Storage

Two key trends shaping the future of NAS are diversification and automation.

Diversification: While SAN/NAS convergence offers benefits, businesses recognize that a one-size-fits-all approach may not be optimal. NAS use cases are diversifying, requiring tailored solutions. NAS offerings need to cater to specific needs, such as backups, virtualization, data analytics, AI/ML, and demanding databases, each with varying performance, scale, and reliability requirements. Selecting the right NAS platform for the specific task is becoming increasingly critical.

Automation: NAS and file storage diversification introduces management complexities related to data integrity and quality. Data placement on the appropriate storage tier (e.g., NVMe-based NAS for performance, disk-based NAS for capacity, cloud NAS for convenience) is crucial. Automation is essential to ensure data is placed correctly, remains complete, intact, and secure, while minimizing manual intervention.

Despite emerging technologies, NAS is expected to remain a vital storage technology, coexisting with SAN and object storage to address a wide spectrum of technical and business storage needs in the foreseeable future.