Which NAS for which use
A NAS is a small computer dedicated to storing files on your network. What matters most is not the brand but how many drives you need, what you will run on it and how fast your network is. This table summarises the most common setups.
| Use | Bays | Processor and memory | Typical setup |
|---|---|---|---|
| Backups of PCs and phones | 2 | ARM or entry-level Intel, 1-2 GB | 2 × 4 TB drives in RAID 1 |
| Photos, video and Plex or Jellyfin | 2-4 | Intel with integrated graphics, 4 GB | 2-4 drives of 6-8 TB |
| Small office | 4 | Intel or AMD, 4-8 GB, 2.5 Gb network | 4 × 8 TB drives in RAID 5 or SHR |
| Docker and virtual machines | 4 or more | 4 cores, 8-16 GB | NVMe SSDs for cache or a fast volume |
How to read the table
The number of bays decides how far the NAS can grow: with 2 bays you can only swap the drives for bigger ones, while with 4 you can add drives over time. If you are torn between two models, favour the one with expandable memory and an x86 processor, because that is what extends the useful life of the device the most. Work out the usable capacity of each RAID level with the calculator before you buy drives.
Processor: ARM or x86
The cheapest NAS units use ARM processors, for example from Realtek. They are efficient and good enough for file sharing, backups and syncing photos from your phone, but they struggle with Docker, virtual machines or video transcoding.
Models with Intel Celeron, Pentium, N100 or AMD Ryzen chips use a little more power, but run containers without trouble and, in the case of Intel with integrated graphics, can convert video in real time for Plex or Jellyfin. If the NAS is going to be more than a file store, this is the place not to cut corners.
Memory and networking
A basic NAS works with 2 GB of memory, but 4 GB leaves room for apps and 8 GB or more is advisable if you use containers or virtual machines. Check whether the memory can be upgraded and which modules the manufacturer supports.
A 1 Gb port transfers at most about 110-115 MB/s, which is less than a single modern hard drive can deliver. A 2.5 Gb port reaches about 280 MB/s, which you will notice when moving videos or large backups, as long as your computer and your switch also have 2.5 Gb ports.
Brands and software
Synology has the most polished and easiest operating system (DSM), with good apps for photos, backups and file sync; on some recent models it restricts or warns about drives that are not on its compatibility list, so check that list before you buy. QNAP gives you more hardware for the same money, but you need to keep a closer eye on security updates.
UGREEN, TerraMaster and Asustor are cheaper alternatives with younger software. If you enjoy tinkering, a mini PC or a server running TrueNAS, Unraid or OpenMediaVault gives you more power per pound or euro, in exchange for more time spent on setup and maintenance.
Power consumption
A 2-bay NAS with drives typically draws 15 to 25 W in use and much less when idle; a 4-bay model is around 30-45 W. Running all year, 20 W adds up to about 175 kWh, roughly 35 euros at 0.20 euros per kWh.
Scheduling drive hibernation during hours when nobody uses the NAS and choosing an efficient processor both lower the bill. You can work out the exact cost with your own tariff in the power consumption calculator.
Security and backups
RAID protects you against a drive failure, but not against deletions, ransomware, theft or fire. Turn on snapshots if the file system supports them and keep a copy away from home following the 3-2-1 rule.
Do not open router ports to reach the NAS from outside: use the NAS VPN server, Tailscale or the manufacturer remote access service, enable two-factor authentication and keep the system up to date. Plugging it into a UPS prevents corruption during power cuts.
Frequently asked questions
Is a NAS better than an external hard drive?
An external drive is fine for an occasional copy of one computer. A NAS is always on, serves several devices at once, runs automatic backups and, with two drives, keeps working if one of them fails.
Which drives should I put in the NAS?
NAS drives that use CMR recording, such as WD Red Plus, Seagate IronWolf or Toshiba N300. Avoid SMR drives in RAID: rebuilds can take a very long time or fail. Our NAS hard drive guide covers this in detail.
Can I start with one drive and add another later?
Yes. Synology with SHR and most other brands let you create the volume with one drive and convert it to RAID 1 when you add the second, although there is no redundancy while you only have one drive.
How much capacity do I need?
Add up the space your photos, videos and backups use today and multiply it by two or three to cover the next few years. With 2 bays in RAID 1, the usable capacity is that of a single drive.