What does a NAS server do?

NAS stands for Network Attached Storage. NAS is essentially a storage device that connects to a LAN and makes storage accessible to other devices on the same network. The main purpose of NAS is to provide centralized data storage and backup for devices connected to the network.

Some key benefits of NAS include:
– Allows access to shared storage devices remotely over a LAN (Local Area Network) or WAN (Wide Area Network).
– Provides a large capacity centralized storage system for multiple clients on the same network.
– Enables data to be easily backed up, stored and shared between multiple devices.
– Scalable storage capacity as more disks can be added to NAS.
– Provides an efficient file sharing solution without requiring a dedicated server.

The origins of NAS date back to the late 1990s when Auspex introduced the first NAS systems designed for NetWare servers. According to Molify, NAS was introduced along with NetWare’s early file-sharing capabilities for enterprise environments. Through the 2000s, NAS evolved to incorporate new hardware and software capabilites making it more affordable and accessible.

NAS vs Other Storage

Network Attached Storage (NAS) has some key differences compared to other data storage systems like Storage Area Networks (SAN), Direct Attached Storage (DAS), and cloud/online storage. Understanding the pros and cons of each can help determine the best solution for your storage needs.

A SAN (Storage Area Network) is a dedicated high-speed network used for data storage. SAN provides block-level access to storage, whereas NAS provides file-level access. SAN is better suited for large enterprises that need high performance, while NAS is more affordable and easier to scale for small businesses. SAN also enables storage consolidation across multiple servers. However, NAS may be more flexible since data is accessed over Ethernet. See SAN vs. NAS: Understanding the Difference for more details.

With DAS (Direct Attached Storage), external drives are directly connected to a computer or server, rather than residing on a network. This makes DAS faster than NAS, but the storage is not shared or centralized. DAS solutions have limited scalability and do not offer data redundancy features that NAS provides. NAS allows easier expansion and administration of storage across a network.

Compared to cloud/online storage, NAS offers more control since data is stored on physical servers on premise rather than remotely. NAS may have lower recurring costs than paying monthly for cloud storage and provides faster local data access. However, cloud storage offers advantages like worldwide accessibility, hands-off management, and seamless scalability. NAS requires maintaining hardware and backups. The choice depends on access needs, budget, and whether centralized on-site storage is preferred.

Common NAS Use Cases

NAS devices are commonly used for the following purposes:

Media Streaming – NAS devices are ideal for media streaming as they can store large media libraries and serve them over the local network to devices like smart TVs, media streamers, game consoles, and mobile devices. Many NAS operating systems have built-in media server software to facilitate easy media streaming.

Data Backup – NAS makes for a great backup destination for your computers and mobile devices. The storage capacity provides ample room for backups, while network accessibility makes backup simple. Some NAS units allow connecting an external drive for additional backup storage.

File Sharing – NAS excels at making files accessible over a local network. Users can access, share, and collaborate on files stored on the NAS. Permissions can be set to control access. This makes NAS useful for small businesses, workgroups, and homes.

Virtual Machine Storage – With their large storage pools, high availability, and shared network access, NAS devices are well-suited for storing virtual machine files such as VMDKs. This provides a central location for virtual machine storage that can be accessed by multiple hosts.

NAS Hardware Components

The key hardware components in a NAS server include:

Hard Drives

NAS devices typically use regular off-the-shelf hard disk drives (HDDs) like ones used in desktop computers. High capacity drives in larger RAID arrays allow NAS devices to offer storage capacities from 4TB to 40TB or more. Some NAS devices also support solid state drives (SSDs) for improved performance.

RAID Arrays

NAS devices arrange hard drives in RAID (redundant array of independent disks) configurations to provide features like redundancy, improved performance, or increased storage capacity. Common RAID levels used in NAS include RAID 1 (disk mirroring), RAID 5 (distributed parity), and RAID 6 (dual parity). The RAID level determines how many disk failures can be tolerated before data loss occurs.

Network Interfaces

NAS devices have built-in network interfaces that allow them to connect to a local network, usually via Ethernet or WiFi. Many NAS devices have multiple 1GbE ports for link aggregation to improve bandwidth, while higher end models may have 10GbE, 40GbE, or faster ports.


The processor in a NAS device handles file transfers, encryption/decryption, RAID calculations, running services like media streaming, and other tasks. Low power processors like ARM chips are common in consumer NAS boxes, while Xeon server-grade CPUs are used in higher performance enterprise NAS.

NAS Software and OS

NAS devices utilize specialized operating systems designed for storage and file sharing. There are proprietary OSes like those from Synology, QNAP, and Asustor as well as open source solutions based on Linux/UNIX such as TrueNAS, OpenMediaVault, and Rockstor.

Some key features to look for in NAS operating systems include:

  • Snapshots for easily rolling back files in case of accidental deletion or ransomware.
  • Replication and syncing to backup files to another NAS or cloud storage.
  • RAID support for storage redundancy.
  • Ability to install extra apps and packages to expand functionality.
  • User and permission management to control access.
  • Encryption options to secure data.
  • Virtualization capabilities to run VMs and containers.
  • Media server and automation features to manage and stream media libraries.

For home users, an OS like Synology DSM provides an easy to use interface and ecosystem of apps. Business users may prefer advanced storage features and ZFS support in TrueNAS. Those wanting more flexibility can run Linux-based solutions like OpenMediaVault on DIY NAS builds.


Setting Up a NAS

Setting up a NAS involves connecting it to your network, configuring the RAID array, and establishing user access controls. Here are the main steps:

First, connect the NAS to your local network using an Ethernet cable or WiFi. Most NAS devices have a setup wizard that will walk you through the network configuration. You’ll need to assign it an IP address, subnet mask, gateway, and DNS servers so it can communicate on your network.

Next, you’ll set up the RAID (redundant array of independent disks) configuration. RAID allows you to combine multiple hard drives for increased storage capacity and/or redundancy. Common RAID types for NAS include RAID 1 for drive mirroring, RAID 5 for distributed parity, and RAID 6 for dual parity. The RAID type determines how your storage is distributed across disks.

After configuring your RAID, you’ll want to set up access controls by creating user accounts and groups. Set permissions for folders and determine which users can access, modify, or admin the NAS. Some NAS operating systems like Synology DSM allow you to create public and private shared folders with custom permissions.

Optional steps include link aggregation for increased bandwidth, backups to external drives, and linking to cloud storage. Port forwarding may be required if accessing the NAS remotely. Once set up, you can manage and maintain the NAS through its web-based dashboard.

Overall, the key setup steps involve networking, RAID creation, and access controls. Refer to your NAS vendor’s documentation for device-specific instructions.[1]

[1] https://geekflare.com/best-nas-software/

Managing and Maintaining NAS

Properly managing and maintaining a NAS is crucial for performance and reliability. Here are some key aspects to focus on:

Adding/Replacing Drives – As storage needs grow, you may need to add additional drives to expand capacity. Most NAS systems support hot-swapping drives, allowing you to add or replace them without powering down the system. Always use compatible drives from the NAS vendor’s compatibility list for best results. Also make sure to follow best practices for migrating data to new drives.

Monitoring Health – Keep an eye on drive health statistics in the NAS interface. Watch for increasing drive errors or slow response times, which can indicate a drive is failing. Replace failing drives promptly to avoid data loss. Many NAS systems also have email/text alerts for drive failures or RAID degradation.

Backups – RAID redundancy is not a substitute for backups. Regularly back up NAS data to an external drive or cloud service in case of failure or accidental deletion. Backup frequency depends on how often new data is added. For example, daily incremental backups plus weekly full backups is a common scheme.

Updates – Maintain the NAS firmware and drives updated to the latest stable versions. Updates provide security patches, bug fixes, and new features. Avoid automatically installing major firmware updates without testing first, as they can sometimes cause issues.

Following best practices for NAS management and maintenance is key for performance, reliability, and avoiding data loss (ProgenyHealth, LLC).

NAS Security

Securing your NAS device properly is critical to protect your data from unauthorized access or corruption. There are several key ways to secure a NAS:


Setting up user accounts and permission levels allows you to restrict access to certain folders or files on the NAS. Give read/write permissions only to those who need it, and limit broader access.

Network Security

Use firewall rules, VPNs, or client IP restrictions to control network access to your NAS. Disable remote admin access and enable TLS/SSL connections. Use a secure network topology.


Encrypt sensitive data stored on your NAS to make it unreadable if accessed without authorization. Some NAS devices support full disk encryption or encrypted shared folders.

Malware Protection

Install anti-malware software to scan for viruses, ransomware, or other malware that could damage NAS data. Perform regular scans and keep protection updated.

For more tips on securing a NAS device, users can harness the full potential of this technology to streamline their data storage and retrieval processes. (https://robots.net/computing-and-gadgets/pcs-and-laptops/how-to-connect-network-attached-storage/)

NAS vs Cloud Storage

When it comes to data storage, two popular options are Network Attached Storage (NAS) devices and cloud storage services. Both offer benefits, so which is better depends on your specific needs.

On-premises NAS devices store data locally, often with redundancy and backup capabilities built in. This allows fast access speeds since data doesn’t need to be transferred over the internet. NAS can provide always-on availability as long as the power and network connection are intact. Some key strengths of NAS include:

  • Full control over hardware and software.
  • Physically accessible for data recovery.
  • Potentially faster speeds than cloud storage.
  • Doesn’t rely on internet connectivity.

Cloud storage services store data remotely on servers owned and operated by the provider. Data is accessible from anywhere with an internet connection. Cloud storage can scale flexibly to accommodate growth and offers subscription-based costs rather than large upfront investments. Benefits of cloud storage include:

  • Accessibility from anywhere with an internet connection per NAS vs. cloud storage: Which is better for your business?
  • Requires no hardware purchase or maintenance.
  • Potentially lower overall costs.
  • Integrates across devices and operating systems.
  • Built-in redundancy and disaster recovery.

For backup, archiving, and availability, NAS and cloud both have advantages. NAS allows on-site backup that is immediately accessible. Cloud backup offers an off-site copy for disaster recovery. For archiving infrequently accessed data, cloud storage’s scalability and lower costs may give it an edge. Using both together provides on-site and off-site copies for comprehensive data protection.


In summary, network attached storage servers provide centralized storage and file services to other devices over a network. Their key capabilities include:

  • Shared file access – NAS allows multiple users and devices to access files and folders on the server.
  • Backups – Automatic backup of computers and devices to the NAS for protection against data loss.
  • Media streaming – Media files stored on the NAS can be streamed to media players.
  • Remote access – Users can access NAS data securely over the internet when away from home.
  • RAID support – NAS can have multiple drives for redundancy to protect against drive failure.
  • Easy expansion – Storage capacity can be easily expanded by adding more drives.

For home users, NAS is ideal for centralized file storage, backups, media streaming and remote access. Businesses can benefit from the shared storage, backups, streamlined collaboration, and ability to scale up storage on a NAS server. With its centralized storage and administration, NAS is an indispensable storage solution for many use cases.