NAS Buying Guide for Beginners: How to Choose
A beginners two-bay NAS fits phone backups, family photos, documents, and basic file sharing. Choose a full-featured two-bay model when you need Docker, virtual machines, faster networking, M.2 storage, or expandable memory. Move to four or more bays when capacity growth and RAID 5, RAID 6, or RAID 10 matter more than a smaller footprint.
Quick Answer: Which NAS Setup Fits You?
| What you need | Best starting point | Main limitation |
|---|---|---|
| Phone backup, family photos, documents, and file sharing | UGREEN DH2300 | Limited advanced applications and hardware expansion |
| Docker, Plex, virtual machines, or self-hosted services | UGREEN DXP2800 | Two SATA bays limit capacity growth and RAID options |
| Virtual machines and several containers | UGREEN DXP4800 GT | Higher enclosure, drive, backup, and network costs |
How Many Drive Bays Do You Need?
Drive bays determine how many SATA hard drives or SSDs the NAS can hold. They affect storage capacity, RAID options, future growth, power use, and the number of drives you must buy.
Two Bays for Backup and Everyday Home Storage
A two-bay NAS is the practical starting point for households. With two matching drives, RAID 1 writes the same data to both drives. If one drive fails, the storage pool remains available while you replace the failed drive.
Current UGREEN two-bay models support Basic, JBOD, RAID 0, and RAID 1. Basic, JBOD, and RAID 0 provide no drive-failure redundancy.
Choose two bays when:
- Your expected library fits comfortably on one drive.
- RAID 1 provides enough drive-failure tolerance.
- You value a smaller system and lower drive cost.
- You do not expect rapid storage growth.
Two bays become restrictive when the required usable capacity exceeds one practical drive size or when you need RAID 5, RAID 6, or RAID 10.
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Four Bays for More Capacity and RAID Flexibility
A four-bay NAS supports configurations that use drive capacity more efficiently or tolerate additional failures. UGREEN four-bay models can support RAID 5, RAID 6, and RAID 10.
With four matching 8TB drives:
| RAID configuration | Decimal capacity before overhead | Approximate binary capacity | Drive-failure tolerance |
|---|---|---|---|
| RAID 5 | 24TB | 21.8TiB | One drive |
| RAID 6 | 16TB | 14.6TiB | Two drives |
| RAID 10 | 16TB | 14.6TiB | One drive in each mirror pair |
RAID 5 offers the most usable capacity of these protected configurations, but a drive fails, rebuilding onto a replacement reads every sector of every surviving drive, which takes many hours or several days at large capacities.
RAID 6 provides dual-parity protection. RAID 10 provides strong performance and faster rebuild behavior, but two failures in the same mirror pair can still take the array offline. See our UGREEN RAID guide for the complete decision rules.
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How Much Usable Storage Do You Need?
Begin with the data you already have, then estimate how much you will add during the next three to five years.
For example, a household with 4TB of existing photos, videos, computer backups, and documents should not build a storage pool with only 4TB available. Account for new files, device backups, file versions, snapshots, application data, and free working space.
RAID also reduces usable capacity:
- RAID 1 capacity equals the size of one drive.
- RAID 5 capacity equals the total capacity of all drives minus one drive.
- RAID 6 capacity equals the total capacity minus two drives.
- RAID 10 normally provides half of the raw capacity.
Use the UGREEN RAID Calculator to estimate capacity for your exact drive count, drive size, and RAID level.
What Does Maximum Storage Mean?
A product’s listed maximum storage may combine SATA drives and M.2 NVMe SSDs.
| Model | Maximum SATA capacity | Maximum M.2 capacity | Listed maximum |
|---|---|---|---|
| DH2300 | 2 × 32TB = 64TB | None | 64TB |
| DXP2800 | 2 × 32TB = 64TB | 2 × 8TB = 16TB | 80TB |
| DXP4800 GT | 4 × 32TB = 128TB | 2 × 8TB = 16TB | 144TB |
These are raw maximums. RAID, system partitions, file-system metadata, and binary unit conversion reduce the capacity displayed as available.
M.2 SSDs can be used for fast storage pools or caching on supported models. An SSD assigned as cache does not add its full capacity to the main storage pool.
What Network Speed Do You Need?
1GbE is sufficient for automatic backups, documents, photo storage, and ordinary household file access.
2.5GbE is a useful upgrade for moving large files between a capable computer and NAS. The computer needs a 2.5GbE port or adapter, and the switch or direct connection must support the same speed.
10GbE is most useful for SSD storage pools, active creative projects, large sequential transfers, or several simultaneous users. A typical four-drive HDD array will not sustain the full 1.25 GB/s link rate. Buying a 10GbE NAS without upgrading the client and network will not improve transfer speed.
| Network port | Theoretical ceiling | Practical context |
|---|---|---|
| 1GbE | 125MB/s | Around 110MB/s for suitable large-file transfers |
| 2.5GbE | 312.5MB/s | Can approach 280MB/s with compatible clients, switches, and storage |
| 10GbE | 1.25GB/s | Actual speed depends heavily on the drives, RAID, client, switch, and workload |
Which Hard Drives Should You Buy?
For RAID, use compatible NAS-rated CMR hard drives. CMR drives handle sustained writes and RAID rebuilds more predictably than SMR drives.
We recommend against SMR drives in RAID because heavy rewrites can cause sharp performance drops and increase the risk of array instability. Check the exact model number in our UGREEN NAS compatibility list before ordering.
Use matching drives when possible. If a RAID array contains different capacities, usable space is normally calculated using the smallest member. One 8TB drive combined with larger drives can leave substantial capacity unused.
Our guide to choosing NAS hard drives explains CMR, workload ratings, warranty length, noise, heat, and drive capacity in more detail.
Before building the final storage pool and copying irreplaceable data, run S.M.A.R.T. short and extended tests on every new drive. Stop if a drive reports reallocated sectors, pending sectors, repeated read failures, or a failed diagnostic.
RAID keeps data available through certain drive failures. It does not recover files deleted by mistake or lost to ransomware, theft, fire, storage-pool corruption, or failure of the entire NAS. Keep an independent backup of important data.
What Should You Include in Your NAS Budget?
The enclosure is only one part of the total cost. Include:
- NAS enclosure
- Compatible hard drives or SSDs
- Usable capacity after RAID
- Independent external or cloud backup
- UPS for safe shutdown during a power outage
- Possible memory or network upgrades
- Replacement drives
- Electricity
Power consumption varies by drive count and workload. Our current lab-rated figures are:
| Model | Drive access | Drive hibernation |
|---|---|---|
| DH2300 | 13.72W | 3.3W |
| DXP2800 | 16.38W | 5.24W |
| DXP4800 Plus | 42.36W | 18.12W |
These measurements used a Seagate 2TB hard drive. A fully populated system, active containers, virtual machines, RAID activity, network traffic, cooling, and disabled hibernation can increase consumption.
Also consider where the NAS will operate. More drives generate additional noise and heat, so a bedroom or quiet workstation may be the wrong location for a heavily used four-bay system.
Frequently Asked Questions
How Many Drive Bays Should a Beginner Choose?
Choose two bays for phone backup, documents, family photos, and moderate storage growth. Choose four bays when you need more usable capacity, RAID 5 or RAID 6, or room to add drives without immediately replacing every installed drive.
Can I Start a NAS With One Drive?
Yes. NAS can start with one drive in a Basic storage pool, but that configuration has no drive-failure redundancy.
Does RAID Back Up My NAS Data?
No. RAID maintains availability through specific drive failures. It does not protect files from deletion, ransomware, corruption, theft, fire, or complete NAS failure. Important data still needs a separate backup.
Can I Mix Different Drive Sizes in a NAS?
Compatible drives of different sizes may work together, but standard RAID normally calculates capacity using the smallest drive.
