NAS Buying Basics: Bays, RAID and Drives
A NAS is a small always-on computer that shares its drives over your network; the number of bays sets your space and how many drive failures it survives.
By Andrian ChengContributing writer.
On this page
What is a NAS
NAS stands for network attached storage. It is a small computer built around one or more hard drive bays, plugged into your router instead of into one PC. Every device on the network can reach its files, and it keeps running backups and media sharing while your computers are off.
NAS vs external hard drive
| External hard drive | NAS | |
|---|---|---|
| Connects to | One computer, by USB | Your network, by Ethernet |
| Shared by | Whoever plugs it in | Every device on the network, at once |
| Protection if a drive fails | None with a single drive | Possible with two or more drives in RAID |
| Runs on its own | No | Yes: backups, sync, media serving |
| Cost | Lower | Higher: the box, plus drives |
An external drive suits one computer's backups. A NAS fits when several devices share files or a drive failure must not cost you data.
How many bays NAS do I need
Bays are the slots for drives. More bays mean more space and more ways to protect it. The protection comes from RAID, which spreads data across drives. Synology lists these common types:
| RAID type | Drives needed | Drive failures it survives | Usable space |
|---|---|---|---|
| RAID 1 | 2 | 1 | One drive's worth |
| RAID 5 | 3 or more | 1 | All drives but one |
| RAID 6 | 4 or more | 2 | All drives but two |
| RAID 10 | 4 or more, even number | 1 per mirrored pair | Half the drives |
Synology's own SHR (Synology Hybrid RAID) does a similar job and can mix drives of different sizes with less wasted space; SHR-2 needs at least four drives and survives two failures.
Here is how that works out with four 8TB drives, using Synology's formulas: RAID 5 leaves 24TB usable, while RAID 6 and RAID 10 each leave 16TB. A 2-bay NAS in RAID 1 with two 8TB drives leaves 8TB.
So, as a rule of thumb:
- 2 bays: mirrored storage for one household; half the raw space goes to protection.
- 4 bays: room for RAID 5 or SHR, and space to grow.
- 8 bays and up: large media libraries, small offices, or two-drive protection with RAID 6.
Of the 469 NAS devices listed on Wiki Shopping on October 26, 2026, 345 state a bay count. 4 bays leads with 93, then 2 bays with 60, 12 bays with 57 and 8 bays with 42.
Other things to check
- Drives included or not: a diskless NAS lets you pick your own drives. On Wiki Shopping, 110 are listed as diskless and 140 with drives included.
- Desktop or rackmount: 123 are desktop boxes and 146 are rackmount units for a server rack.
- Network speed: the fastest port sets how fast files move. On Wiki Shopping, 70 top out at 1GbE, 83 at 2.5GbE and 140 at 10GbE. Your router or switch needs a matching port to use the extra speed.
RAID protects against a failed drive, not against deleting a file or a fire, so keep a second backup somewhere else.
How we count
Bays, drives, body and port speed are read from each device's store listing. Devices that do not state a value are left out of that count. Usable space examples use Synology's published formulas.
Shop by spec
NAS Devices
2 Bays, Diskless
+Two drive bays for a mirrored or expandable setup
+Diskless design lets you choose your own drive size
+Private cloud storage for home and small business use
−Ships diskless, so drives must be bought separately
$622.00-25%List: $829.99
as of 11/04/2026 10:09 PST - DetailsProduct details
$622.00as of 11/04/2026 10:09 PST - Details
View on AmazonPros
+Two drive bays for a mirrored or expandable setup
+Diskless design lets you choose your own drive size
+Private cloud storage for home and small business use
Cons−Ships diskless, so drives must be bought separately
Compared with this page−2 bays: 238 of the 299 here have more bays
How pros and cons are picked (About: Disclaimer)Other stores (1)
Best BuyVisit store
About this product
- Start Small, Scale Massive - Begin with 2 drives, expand to 140TB total capacity using DX525 expansion as your media library grows
- Multi-Layered Data Protection - Combine RAID redundancy, automated backups and snapshot technology to prevent data loss from any cause
- Multi-site Surveillance - Manage security cameras across home or small business with advanced analytics and unlimited retention periods
- Add 5 extra drive bays for up to 140 TB of storage with one DX525 expansion unit
- Professional Surveillance System - Monitor home or business with support for 30 IP cameras, motion detection and secure remote access
- 3-Year Warranty - Premium hardware reliability for users who depend on continuous access to their data
Spec score 7.2
4 Bays, 2.5GbE, Diskless, Desktop
+Four drive bays for expanded storage
+2.5GbE network port for faster transfers
+Desktop form factor for placing on a desk or shelf
−Ships diskless, so drives must be bought separately
$779.77-12%List: $889.99
as of 11/04/2026 10:06 PST - DetailsProduct details
$779.77as of 11/04/2026 10:06 PST - Details
View on AmazonSpec score7.2
Pros
+Four drive bays for expanded storage
+2.5GbE network port for faster transfers
+Desktop form factor for placing on a desk or shelf
Cons−Ships diskless, so drives must be bought separately
Compared with this page−4 bays: 169 of the 299 here have more bays
How pros and cons are picked (About: Disclaimer)Other stores (1)
Best BuyVisit store
About this product
- Supports drives on the model's official compatibility list
- Up to 522/565 MB/s sequential read/write throughput supports stable data transfers.
- Dual 2.5GbE ports provide fast network transfer speeds and increased redundancy.
- Leverage built-in file and photo management, data protection, virtualization, and surveillance solutions.
- Backed by Synology's 3-year limited hardware warranty.
Spec score 8.7
6 Bays, Intel, 64GB, 10GbE
+Six bays for substantial storage capacity
+64GB RAM for heavier workloads
+Two M.2 slots for SSD caching
−Drives not included, so storage must be bought separately
$3,599.99
as of 11/04/2026 03:05 PST - DetailsProduct details
$3,599.99as of 11/04/2026 03:05 PST - Details
View on AmazonSpec score8.7
Pros
+Six bays for substantial storage capacity
+64GB RAM for heavier workloads
+Two M.2 slots for SSD caching
+10GbE network port for fast transfers
+Docker support for running containerized apps
Cons−Drives not included, so storage must be bought separately
Compared with this page+10GbE: the highest fastest port of the 271 here
+64GB memory: only 2 of 229 here have a higher memory
+Runs Docker: only 27 of 413 here have one
+M.2 SSD slots: only 70 of 413 here have one
How pros and cons are picked (About: Disclaimer)Other stores (1)
UgreenVisit store
About this product
- 【Built for Creators, NAS Upgraders & Growing Teams】iDX6011 64GB is designed for creators, media professionals, NAS upgraders, and small teams managing larger libraries and more demanding workflows. It combines private local storage, AI-powered data management, backup, collaboration, and advanced NAS services in one platform.
- 【64GB LPDDR5X for Heavy Multitasking】With 64GB LPDDR5X memory, iDX6011 gives users more headroom for running AI tools, multiple NAS services, Docker containers, virtual machines, media applications, and large file workflows simultaneously. It is well suited to users who need more multitasking capacity than the 32GB model.
- 【Local AI for Search, Files, Voice & Photos】Use Universal Search to find local content with natural language, Uliya AI Chat to interact with your data, AI File Organization to sort files, Voice Memos to transcribe and summarize recordings, and AI Photo Management to recognize, classify, and search large photo libraries.
- 【Intel Core Ultra 5 for AI & Creative Workloads】The Intel Core Ultra 5 125H delivers 14 cores, 18 threads, speeds up to 4.5GHz, and 33 TOPS of overall AI performance. Together with 64GB LPDDR5X memory, it provides a strong platform for local AI, media workflows, multitasking, virtualization, and everyday NAS services.
- 【Up to 208TB Centralized Storage】Six SATA bays and two M.2 slots provide up to 208TB of total storage for creative assets, business documents, backups, media libraries, and long-term archives. Flexible RAID options including RAID 0/1/5/6/10 help users balance usable capacity, performance, and data redundancy.
- 【High-Bandwidth Creative Connectivity】Dual 10GbE LAN, dual Thunderbolt 4, SD 4.0, USB 3.2, PCIe Gen 4 x8 expansion, and 8K HDMI help connect workstations, cameras, storage devices, and displays. Import media, transfer large files, and centralize creative projects for more efficient team workflows.
- 【One UGOS Pro System for Work & Backup】Manage files, backups, shared folders, permissions, snapshots, photos, apps, Docker, virtual machines, and storage through UGOS Pro. With support across Windows, macOS, iOS, Android, Web, and TV, teams can access and manage their private data from multiple devices.
Spec score 8.6
4 Bays, AMD, 8GB, 10GbE
+Four drive bays for a larger storage pool
+M.2 slot for an SSD cache or fast storage
+10GbE network port for fast transfers
−Diskless, drives must be bought separately
$659.99
as of 11/04/2026 10:09 PST - DetailsProduct details
$659.99as of 11/04/2026 10:09 PST - Details
View on AmazonSpec score8.6
Pros
+Four drive bays for a larger storage pool
+M.2 slot for an SSD cache or fast storage
+10GbE network port for fast transfers
+Docker support for running extra apps
+Media features for home media streaming
Cons−Diskless, drives must be bought separately
Compared with this page+10GbE: the highest fastest port of the 271 here
+Runs Docker: only 27 of 413 here have one
+M.2 SSD slots: only 70 of 413 here have one
−4 bays: 169 of the 299 here have more bays
−8GB memory: 121 of the 229 here have a higher memory
How pros and cons are picked (About: Disclaimer)Other stores (1)
UgreenVisit store
About this product
- 【High-Performance Multitasking for Speed & Endurance】Powered by AMD Ryzen Embedded R2514, 4 cores, 8 threads, and up to 3.70GHz, with 8GB DDR4 RAM expandable to 64GB, DXP4800 GT handles backups, media processing, Docker apps, and multi-user workloads smoothly. Dual 10GbE networking and high-speed SSD expansion deliver fast transfers, stable streaming, rapid backups, and local-like 4K/8K editing directly from the NAS.
- 【UGOS Pro with Expandable Media & App Ecosystem】UGOS Pro makes NAS management simple with guided setup, a clean interface, and helpful on-screen tips. Beyond files, photos, backup, and search, it supports Docker, virtual machines, and SAN Manager, letting users expand into Plex, Emby, Jellyfin, Home Assistant, web hosting, and other self-hosted workflows-all managed through the UGREEN NAS app across phone, tablet, computer, and TV.
- 【Surveillance Center Built-In】Connect compatible IP cameras to DXP4800 GT and turn your NAS into both the storage drive and control center for home or small-business security. UGREEN Surveillance Center only supports ONVIF/RTSP cameras, live multi-view, PTZ control, event detection, recording, and timeline playback from one NAS-based platform. Footage stays stored locally, so you can review, manage, and share access without separate camera apps or cloud subscriptions.
- 【USB & SD Instant Backup】Built-in SD card slot lets creators import photos and videos without an external card reader. Simply insert an SD card into the NAS, open the UGREEN NAS app, and copy or back up files to your selected folder in just a few clicks. Combined with USB-A 10Gbps, USB-C 10Gbps, USB 2.0, and 4K HDMI connectivity, DXP4800 GT helps you quickly transfer camera footage, media assets, or surveillance files-saving time and simplifying your workflow without relying on a computer.
- 【Local Privacy, Pro-Grade Security】Store files locally on DXP4800 GT instead of third-party cloud servers, with local account mode for LAN-only access when needed. TLS/SSL, RSA, AES, and SHA-512 help secure logins and data transfers, while Security Manager, and flexible permissions provide continuous protection. RAID support adds data redundancy to help reduce the risk of data loss and improve file recovery in the event of drive failure.
- 【144TB Storage-Say Goodbye to Full Devices】DXP4800 GT supports 4 drive bays for SATA drives up to 32TB each, with up to 2 of the same bays compatible with U.2 NVMe SSDs, plus up to 16TB via two M.2 SSD, for up to 144TB total capacity. Store photos, videos, work files, movies, security footage, and smart home data in one place. Free up phones and computers, stop juggling external drives, and say goodbye to “storage full” stress. *Drives not included. Purchase HDDs/SSDs from a third party.
- 【Dual 10GbE, Up to 2.5GB/s】Each 10GbE port supports up to 10Gbps, or about 1.25GB/s theoretical speed. With Link Aggregation on compatible network equipment, dual ports can provide up to 20Gbps aggregate bandwidth, or about 2.5GB/s theoretical throughput, enabling smoother large file transfers, faster backups, balanced multi-user access, and efficient 4K/8K workflows.
- 【Important Notes Before Purchase】DXP4800 GT supports ECC RAM upgrade to help detect and correct memory errors during long-term operation. The pre-installed RAM is non-ECC, so ECC error correction requires a compatible ECC RAM upgrade. Drives not included, please purchase HDDs and SSDs from a third party. Plex can run via Docker and requires manual setup.