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The short answer
Buy a two-bay unit for backups and file storage, or four bays if you want redundancy plus room to grow. Choose drives rated for continuous operation. And understand that RAID protects against a drive failing, not against deletion, ransomware or fire, so a NAS still needs its own backup.
A NAS is a small computer with drive bays that sits on your network and serves files. For a household, the useful jobs are automatic backups from every computer, a single place for photos and documents, media streaming, and an alternative to paying monthly for cloud storage. It is a considerable step up in capability from an external drive, and a considerable step up in complexity too.
Do you need one?
Probably not if: you have one computer, your photos are in cloud storage, and an external drive plus that cloud copy covers you. That arrangement is simpler and cheaper.
Probably yes if: several people generate files, you have a large photo or video library, you want backups to happen without anyone remembering, you are paying meaningfully for cloud storage, or you want to run media streaming at home.
How many bays
- One bay: effectively a network drive. Cheap, and no redundancy at all.
- Two bays: the sensible minimum. Mirror the drives so one can fail without data loss, or use them as separate volumes.
- Four bays: redundancy plus growth, and the ability to survive a drive failure while keeping most of the capacity. The usual recommendation for a household that will keep it for years.
- More: for media libraries and small businesses, and it increases power consumption and noise accordingly.
The practical advice is to buy more bays than you need now, because migrating to a larger unit later is tedious, and drives can be added over time.
RAID is not a backup. Mirroring protects against a drive failing. It does not protect against deleting a folder, ransomware encrypting your files, a power surge destroying the unit, theft or fire, because all of those affect both drives identically. A NAS needs backing up, ideally to an external drive kept elsewhere or to cloud storage.
Units worth considering
Synology DiskStation DS925+ four-bay NAS
Synology’s advantage is software rather than hardware. The backup tools, the photo library, the sync clients and the mobile apps are genuinely good and well documented, which matters enormously on a device you configure once and then depend on for years. Four bays covers redundancy plus growth.
UGREEN NAS DXP2800 two-bay for home users
The newer entrants compete on hardware specification, and this offers a faster processor and more memory than equivalently priced alternatives. If you want to run containers or transcode video, that matters. The software ecosystem is younger, which is the trade-off to weigh.
UGREEN DXP4800 Plus four-bay NAS
Media serving is where processing power becomes relevant, because converting video on the fly for a phone or an older TV is demanding. Four bays plus a capable processor suits a household that wants a media library as well as backups.
UGREEN NAS DH2300 two-bay for beginners and personal use
A reasonable first NAS if the goal is automatic phone photo backup and a shared folder, rather than running services. Two bays mirrored gives you protection against a drive failure, which is the main thing an external drive does not offer.
Seagate IronWolf 4TB NAS internal hard drive
NAS units are usually sold without drives, and using ordinary desktop drives in one is a common and expensive mistake. NAS-rated drives handle continuous operation and the vibration of several drives in one chassis, and they carry firmware suited to RAID error handling.
What we liked
- Backups happen automatically for everyone in the house
- One place for photos and documents
- Replaces a recurring cloud storage bill over time
- Media streaming and remote access from anywhere
What we didn't
- More complex than an external drive
- RAID is not a backup and people believe it is
- Drives are a significant additional cost
- Always-on power consumption and some noise
Setting one up sensibly
Use NAS-rated drives
Desktop drives fail sooner in multi-bay enclosures and handle errors in ways that can drop them out of an array.
Buy drives from different batches or brands
Drives from the same batch can fail at similar times, which is precisely what redundancy is meant to protect against.
Set up automatic backups from every computer
This is the main benefit and the one people postpone. Both Windows and macOS back up to a NAS natively.
Back up the NAS itself
To an external drive kept elsewhere, or to cloud storage. This is not optional, and it is what makes the arrangement a real backup strategy.
Secure remote access carefully
Use the manufacturer’s relay service or a VPN rather than forwarding ports. NAS units exposed directly to the internet are actively targeted.
Enable notifications and test a restore
You need to know when a drive fails, and you need to know the restore works before you rely on it.
Is a NAS better than cloud storage?
It is different. A NAS is faster on your own network, has no monthly fee, and is in your house, which means fire and theft affect it. Cloud storage is offsite and costs continuously. Most people benefit from both.
Does RAID mean I do not need backups?
No. RAID protects against a drive failing. Deletion, ransomware, theft and fire all destroy every copy on the unit simultaneously. A NAS needs its own backup elsewhere.
How many drive bays should I buy?
Two as the minimum for redundancy, four if you want room to grow. Migrating to a larger unit later is tedious enough that buying ahead is usually worth it.
Can I use ordinary desktop hard drives?
You can, and they are more likely to fail early and to behave badly in an array. NAS-rated drives are designed for continuous operation and vibration, and the price difference is modest.
How much power does a NAS use?
Typically 20 to 40 watts with drives spinning, less when idle with drives asleep. Over a year that is a modest cost, comparable to a couple of light bulbs left on.
How to choose
Buy two bays for backups and four if you want growth and media. Choose the software ecosystem you are willing to live with, because that is what you interact with daily. Fit NAS-rated drives from different batches. Then set up automatic backups from every computer, back the NAS up somewhere else, and test a restore once so you know it works.
