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Choose a NAS when several computers or people need the same files over a network. Choose an external hard drive when you need the simplest direct-attached backup or a copy you can unplug and store elsewhere. For many households and small teams, the strongest design uses both: the NAS holds active shared files, while an external drive or offsite destination stores an independent backup.
The important distinction is not simply capacity. A NAS is a networked storage system that requires configuration, compatible drives, network access and ongoing administration. An external drive is a directly attached storage device that is easier to connect and move, but it does not create shared network folders by itself. RAID in a NAS can improve availability after some drive failures, yet it is not a backup.
NAS vs. external hard drives: which is better for backups and shared files?
The better choice depends on the job you need to perform.
| Need | Better starting point | Why | Main caveat |
|---|---|---|---|
| Several users or devices need shared files | NAS | Network shares, user permissions and file protocols provide a central location. | It requires setup, network access and maintenance. Remote access is a separate security and configuration decision. |
| Back up one computer with minimal setup | External hard drive | It connects directly and supports straightforward manual or scheduled copies. | You must manage backup frequency, versions and whether the drive stays connected. |
| Keep a copy of NAS data | External USB drive or another independent destination | NAS backup software can copy data to attached USB storage or other destinations. | A permanently connected local copy remains exposed to theft, physical damage and some malware. |
| Need collaboration and backup protection | NAS plus external or offsite backup | The NAS serves active files while another device or location preserves a separate copy. | It costs more and requires a written schedule and a tested restore process. |
Do not generalize capacity, throughput, noise, energy use or price from the category alone. Those figures depend on the selected NAS model, drive count, disks, network equipment, client devices and workload.
#1 Best Overall
- Secure private cloud - Enjoy 100% data ownership and multi-platform access from anywhere
- Easy sharing and syncing - Safely access and share files and media from anywhere, and keep clients, colleagues and collaborators on the same page
- Automated Backup Protection - Set-and-forget backups for Macs, PCs and mobile devices to multiple destinations including cloud and external drives
- Home Security System - Record and monitor your property 24/7 with support for multiple IP cameras and remote viewing
- 2-Year Warranty - Reliable hardware backed by Synology's expert customer support team and ongoing software updates
What a NAS provides
Centralized shared folders
A NAS is a storage computer connected to your local network. Instead of plugging a disk into one computer, you create folders that authorized computers and people can open through the network. Synology DSM, for example, supports shared folders, user and group permissions, and network file protocols including SMB, AFP and NFS. Exact features and limits vary by model and software version.
This arrangement is useful for a family photo library, a team project directory, a media collection or documents that must be available from multiple computers. A file can remain in one central location rather than being copied manually between laptops.
Permission management
With a NAS, access can be assigned to individual users or groups. You can give a household member access to family documents while keeping an administrator folder private, or allow a project group to edit a shared directory without exposing unrelated folders. Permission design should follow the least-privilege principle: grant each person only the folders and actions required for their work.
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Keep an inventory of accounts, group membership and folder permissions. When someone leaves a team or no longer needs access, remove or change the account instead of relying on everyone to stop using an old shared password.
Dependence on the network
A NAS is only convenient when the network is available. A failed router, damaged Ethernet cable, wireless dead zone or overloaded network can make an otherwise healthy NAS appear unavailable. Wired connections are generally the more predictable choice for a fixed NAS, but the useful client speed still depends on every link between the NAS and the computer.
Access from outside the home or office is not automatic. Remote access introduces additional account, authentication and exposure decisions and should be configured only after local sharing works reliably. If your requirement is simply to carry a copy to another location, an unplugged external drive is usually less complicated.
What an external hard drive provides
Direct connection and portability
An external hard drive connects directly to a computer, normally over USB. That makes it a natural choice for a local backup of one desktop or laptop, an archive you access occasionally, or a copy that can be disconnected and stored separately. A disconnected drive is not reachable by a network attacker while it is unplugged, although it still needs protection from loss, theft, damage and unauthorized access.
Rank #2
- 【Reliable External Storage System for Individuals and business】The 3.5 hard drive enclosure supports 2.5/3.5 inches HDD and SSD, max capacity up to 20TB for each hard drive, it's a ideal external hard drive enclosure for personal or enterprise using.Save space on your desktop or laptop.
- 【No heat】The sata enclosure built in Aluminum-Alloy materials and 2 inch Fan.Maximize the security of your data.Fan noise is around 40-50 decibels, not recommended if you are very sensitive to noise.
- 【Up to 5Gbps】This dual bay enclosure equips with advanced chips and USB 3.0 output interface.Transfer 1G files in 3-5 seconds with USB 3.0 Ports, which is 10 times faster than USB 2.0.
- 【Hot Swappable Convenience】The HDD enclosure supports hot swapping, allowing users to replace hard drives without powering off the device. This feature enhances convenience and efficiency in data transfer processes.
- 【Tool-Free Installation】Featuring a tool-free hard drive tray design, the external hard drive enclosure enables easy installation and removal of hard drives without requiring additional tools. Plug and play! No fuss, no muss!
Simple does not mean automatic
The device itself does not decide what to copy, how often to copy it or how many historical versions to retain. Use your computer’s backup software or a documented manual process, and confirm that it is actually running. A drive that is connected once a year and copied without verification is not equivalent to a continuously maintained backup system.
For a single computer, define the folders, applications or system state that must be recoverable. Set a recurring schedule if your backup software supports one, and leave enough time for the copy to complete. If the drive is normally disconnected, reconnect it on the schedule and safely eject it afterward.
Using a NAS for shared files
Plan the layout before installing
List who needs access, which folders they need and whether files are edited by one person or many. Separate personal folders, team folders and administrative data. Decide which files should be available to every household member and which should remain restricted. This plan prevents a common mistake: creating one unrestricted share and later trying to repair permissions after sensitive files have already been exposed.
Choose storage and network requirements
A two-bay NAS is a natural category for readers who need network shares and permissions, but the right choice depends on household or team size, required capacity, drive redundancy, network equipment and willingness to administer the device. Confirm the NAS model’s supported drive types, maximum capacity, USB behavior and software version before purchase. A product category does not establish a universal best model.
Configure users, groups and protocols
- Connect the NAS to the network and complete the vendor’s initial administrator setup.
- Create individual user accounts and groups that match the access plan.
- Create separate shared folders for each data category.
- Assign read or read/write permissions to users and groups, then review inherited permissions.
- Enable the file protocols required by your client devices. DSM documentation lists SMB, AFP and NFS; availability and behavior can differ by model and software release.
- Connect a test computer with a normal user account and confirm that permitted folders open while restricted folders remain inaccessible.
Menu names and locations change between DSM releases and NAS vendors, so follow the documentation for the exact model rather than assuming that a setting shown for one device exists on another.
Set expectations for availability
A NAS can make files available to several devices at once, but it is still one system that can fail or become unreachable. Keep a separate copy of irreplaceable data, document how to reach it, and identify who will perform updates, replace failed drives and test restores.
Backing up a computer to an external drive
- Choose a drive with enough usable capacity for the data set and the historical versions you intend to keep. Compare usable capacity, not only the number printed on the box.
- Connect the drive directly to the computer and format it using a file system supported by your operating system and backup application.
- Select the folders or system backup option you need. Include data that is difficult or impossible to recreate, not merely files that are convenient to copy.
- Set a recurring schedule when your software supports it, or write a calendar reminder for a manual workflow.
- After the first run, open several backed-up files and verify that the destination contains the expected dates and folder structure.
- When the backup finishes, safely eject the drive if you are going to store it separately. Keep it in a location protected from heat, moisture, impact and unauthorized access.
A single external drive gives you one local copy. It does not protect against a fire, flood or theft that affects both the computer and the drive stored beside it.
Rank #3
- Entry-level NAS Personal Storage：UGREEN NAS DH2300 is your first and best NAS made easy. It is designed for beginners who want a simple, private way to store videos, photos and personal files, which is intuitive for users moving from cloud storage or external drives and move away from scattered date across devices. This entry-level NAS 2-bay perfect for personal entertainment, photo storage, and easy data backup (doesn't support Docker or virtual machines).
- Set Your Devices Free, Expand Your Digital World: This unified storage hub supports massive capacity up to 64TB.*Storage drives not included. Stop Deleting, Start Storing. You can store 22 million 3MB images, or 2 million 30MB songs, or 43K 1.5GB movies or 67 million 1MB documents! UGREEN NAS is a better way to free up storage across all your devices such as phones, computers, tablets and also does automatic backups across devices regardless of the operating system—Window, iOS, Android or macOS.
- The Smarter Long-term Way to Store: Unlike cloud storage with recurring monthly fees, a UGREEN NAS enclosure requires only a one-time purchase for long-term use. For example, you only need to pay $459.98 for a NAS, while for cloud storage, you need to pay $719.88 per year, $2,159.64 for 3 years, $3,599.40 for 5 years. You will save $6,738.82 over 10 years with UGREEN NAS! *NAS cost based on DH2300 + 12TB HDD; cloud cost based on 12TB plan (e.g. $59.99/month).
- Blazing Speed, Minimal Power: Equipped with a high-performance processor, 1GbE port, and 4GB RAM on Board, this NAS handles multiple tasks with ease. File transfers reach up to 125MB/s—a 1GB file takes only 8 seconds. Don't let slow clouds hold you back; they often need over 100 seconds for the same task. The difference is clear.
- Let AI Better Organize Your Memories: UGREEN NAS uses AI to tag faces, locations, texts, and objects—so you can effortlessly find any photo by searching for who or what's in it in seconds. It also automatically finds and deletes similar or duplicate photo, backs up live photos and allows you to share them with your friends or family with just one tap. Everything stays effortlessly organized, powered by intelligent tagging and recognition.
Backing up a NAS to USB storage
Hyper Backup for versioned copies
Synology documents Hyper Backup as a way to create multi-version backups to USB and other destinations. Versioning matters when a file is accidentally deleted, corrupted or overwritten: the newest copy may contain the mistake, while an earlier version can be restored.
Synology Knowledge Center explains the benefit this way: Having a multi-version local copy gives you the advantage of fast recovery in the event of data corruption or accidental file deletion, since the data copy can be retrieved directly from your Synology NAS.
The statement appears in “How can I back up my Synology NAS?”, last updated May 8, 2026.
USB Copy for a more direct workflow
USB Copy is a more direct copy workflow with a different feature set. It can be appropriate when you want a straightforward transfer between the NAS and an attached USB device rather than a versioned backup repository. Check the selected NAS model and current software documentation to confirm supported jobs, direction and scheduling.
Separate the destination from the source
After a NAS backup completes, disconnect the USB drive when practical. A drive that remains permanently attached is convenient for automated jobs, but it shares some exposure with the NAS. Malware, a power event, theft or physical damage can affect both devices. Rotate more than one drive or place a completed copy in another secure location when the data warrants it.
RAID is not a backup
RAID combines multiple drives to improve availability or capacity according to the selected layout. Depending on the level and the failure, a NAS may continue operating after one drive fails, giving you time to replace the failed disk. That is useful for uptime, but it does not create an independent historical copy.
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Synology cautions: However, even when such measure is taken, RAID crash and hard drive failure might still cause data loss.
A RAID array can be damaged by more than one failed drive, controller or enclosure problems, accidental deletion, file corruption, malware, theft or a site-wide disaster. If a bad file is synchronized across the array, RAID preserves the bad file efficiently.
Use RAID as an availability feature and maintain a separate backup on another device or destination. Never describe a mirrored or parity array as your only backup plan.
Rank #4
- High Speed Data Transmission: The D2-320 hard drive enclosure (a DAS, NOT a NAS) adopts USB 3.2 Gen2 protocol for high-speed data transmission up to 10Gbps. With 2 hard drives in RAID 0, the read/write speed can reach up to 521MB/s (SATA III HDD 8TB x 2). With 2 SSD's in RAID 0, the read speed can reach 1075MB/s (SATA III 1TB SSD x 2)
- Multiple RAID Configurations: The D2-320 is a hardware RAID enclosure and it supports RAID 0, RAID 1, JBOD and SINGLE which can better satisfy various demands of users. In RAID 1, data will be in a mirror backup. When there is a damaged hard drive, you can directly replace the hard drive, and the data will be recovered automatically. This provides an absolute security for the data
- Super-Large Storage Capacity: The D2-320 USB storage enclosure can support up to two 3.5" and 2.5" SATA HDD, as well as 2.5" SATA SSD, with a maximum capacity of 22TB per drive, providing users with up to 44TB (22TB x 2) of storage space
- Intelligent Temperature Control: The D2-320 HDD enclosure has an intelligent temperature-controlled and low-noise fan that automatically adjusts its speed based on the temperature of the hard disk. This feature ensures that the hard disk operates at its best temperature and provides better heat dissipation
- Tool-Free Hard Drive Installation: The D2-320 external hard drive enclosure features a tool-free hard drive tray design that allows for easy installation and removal of hard drives without the need for any tools. Furthermore, the D2-320 incorporates a brand new Push-lock unique design from TerraMaster, which automatically locks the hard drive tray when you insert the hard drive, preventing the hard drive from falling out or disconnecting
Apply the 3-2-1 backup rule
Synology’s guidance recommends the 3-2-1 strategy:
- 3 copies: the working data plus two backup copies.
- 2 storage media: use more than one type of device or storage system.
- 1 offsite copy: keep at least one copy away from the equipment that holds the originals.
This is a rule of thumb, not a published empirical success rate. Its purpose is to avoid a single point of failure. A NAS and an external USB drive in the same room improve separation compared with one NAS, but they do not address a fire, natural disaster or theft affecting the entire site. Synology’s official backup guidance specifically recommends an offsite copy for those events.
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Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How to choose by scenario
One laptop and occasional backups
Start with an external drive. It avoids NAS administration and gives you a direct destination. Use a schedule or calendar reminder, verify restorations and store the drive separately after each run. Add an offsite copy if losing the laptop and the local drive together would be unacceptable.
Two or more computers sharing documents
Start with a NAS if the computers regularly need the same working files. Create accounts and shared folders instead of passing USB drives between people. Budget time for permissions, network troubleshooting, software updates and backups. The NAS should be the working location, not the only copy.
Family photos and media accessed by several devices
A NAS can centralize the library so multiple computers can use one copy. Keep original photos and other irreplaceable files in a versioned backup as well. If family members need access while travelling, treat remote access as a separate project with its own authentication and security review.
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A NAS’s user and group permissions are more manageable than a collection of portable drives. Assign access by group, remove accounts promptly when roles change and record who owns administration. Keep an external or offsite backup that is not writable by every daily user.
Best Value
- 【Advanced Home Data & Media Hub】For advanced home users who need phone backup, file storage, and centralized data management. Centralize family photos, 4K videos, movies, computer backups, and personal files in one place while running multiple apps for home entertainment and everyday data management. Suitable for households with growing digital libraries and multiple NAS use cases.
- 【Built for Creators, Media Servers & Advanced Apps】Powered by the Intel N100 Quad-Core CPU, 8GB DDR5 RAM, 2.5GbE networking, and dual M.2 NVMe slots, DXP2800 handles large files and heavier workloads with ease. Run Docker, virtual machines, and media server applications compatible with Plex—ideal for content creators, tech enthusiasts, and advanced home users managing 4K videos, RAW photos, personal media libraries, and multiple NAS apps.
- 【Up to 80TB for Growing Digital Libraries】 Supports up to 80TB of storage using two HDD bays and two M.2 NVMe SSD slots for family photos, movies, RAW photos, 4K videos, work files, and device backups. AI photo management supports recognition of people, objects, scenes, and locations, album organization, and duplicate photo detection. HDDs and SSDs are not included.
- 【AI-powered Home Surveillance】Turn DXP2800 into a centralized home surveillance hub by connecting compatible network cameras and storing recordings locally on your NAS. AI-powered features include Face Recognition, People Detection, and Pet Detection, helping advanced home users review important events more efficiently while managing home surveillance and personal data in one place.
- 【One data Center Across Your Devices】Keep files from desktops, laptops, phones, tablets, and other devices together instead of scattered across cloud accounts and external drives. Access, back up, organize, and share data across Windows, macOS, Android, iOS, web browsers, and compatible smart TVs—ideal for creators and advanced home users working across multiple devices.
Travel, field work or temporary transfers
An external drive is usually the practical choice because it is portable and works without a shared network. Protect it against drops, heat, moisture and loss, and encrypt it if your operating system and policy support encryption. Do not treat a travel drive as the sole copy of important data.
Ownership and operating burden
| Consideration | NAS | External hard drive |
|---|---|---|
| Initial setup | Requires network connection, storage configuration, accounts, shared folders and permissions. | Usually plug in, format and select it in backup software. |
| Access model | Multiple devices can use network protocols and centralized folders. | Normally attached to one computer at a time unless separately shared by that computer. |
| Portability | Designed to remain in one location; moving it requires shutting down and reconnecting network equipment. | Easy to unplug and store or transport, subject to physical protection. |
| Administration | Requires updates, account management, drive monitoring, backup jobs and recovery planning. | Requires connection scheduling, backup verification and safe storage. |
| Failure isolation | Can use multiple drives and RAID for availability, but still needs an independent backup. | A disconnected copy is isolated from many online threats, but one drive can still fail or be lost. |
| Cost profile | Includes the enclosure, compatible drives, network equipment and ongoing power and maintenance; exact amounts depend on the model and region. | Usually fewer components, but capacity and number of backup copies determine total cost. |
Compare total usable capacity, drive count, redundancy options, network port and client network speed, supported protocols, backup and versioning software, noise, power use, setup effort, portability and ongoing replacement needs. Product-specific prices and performance must be evaluated for the exact models and workload.
Common mistakes and fixes
Using RAID as the only protection
Symptom: Everyone assumes the array makes backups unnecessary. Fix: Create an independent copy on an external drive or another destination and include an offsite copy for site-wide risks.
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Leaving every copy in one place
Symptom: The NAS and backup drive sit beside the same computer. Fix: Disconnect and rotate the local drive, and keep at least one completed copy elsewhere.
Creating one unrestricted shared folder
Symptom: Users can browse documents they should not see. Fix: Create separate folders, groups and least-privilege permissions, then test with an ordinary account.
Confusing synchronization with versioned backup
Symptom: A deletion or corrupted file appears in every location. Fix: Use multi-version backup where recovery from earlier states is required and test that versions can be opened.
Never testing a restore
Symptom: A job reports success, but the files cannot be recovered when needed. Fix: Periodically restore sample files to a separate location and document the procedure.
Choosing capacity without accounting for versions
Symptom: The destination fills sooner than expected. Fix: Estimate working data plus retained versions, temporary space and future growth using the selected software’s behavior, then monitor free space.
A practical backup and restore checklist
- Identify data that cannot be recreated and assign an owner for it.
- Record where the working copy, local backup and offsite copy are located.
- Set a frequency based on how much data you can afford to lose between backups.
- Keep historical versions for files vulnerable to accidental deletion or corruption.
- Separate at least one copy from the network and the primary site.
- Use individual accounts and review permissions when people or roles change.
- Monitor backup completion rather than assuming a connected device is working.
- Restore representative files periodically, including a large file and a recently changed document.
- Document replacement steps for a failed drive, NAS or computer.
Bottom-line decision
Pick an external hard drive when your priority is a simple, direct-attached backup or a portable copy for one computer. Pick a NAS when several people or devices need centralized files with managed permissions over a network. If the files matter, combine them: keep active shared data on the NAS, create versioned backups to an independent external drive or other destination, and maintain an offsite copy. RAID can keep some NAS services available after a drive failure, but only an independent, recoverable backup protects against deletion, corruption and loss of the entire site.
Quick Recap
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