Network Storage at Home: Do You Need It

A NAS, Network Attached Storage, is a box of hard disks connected to the network rather than to one computer. Every device in the house can read it, and it stays on when the computer is off.

Before discussing how to choose one, a prior question: do you actually need one?

When an ordinary drive is enough

For many homes, the answer is an external drive costing a tenth as much.

An external drive is enough when:

• One or two people use it.
• The files are accessed from the same single computer.
• Nothing needs reaching them while that computer is off.

A NAS starts making sense when:

• Several people use the same files and copies are starting to scatter across devices.
• Something needs to write continuously: security cameras most often, and that's among the strongest reasons.
• Files need reading from phones and televisions, not just computers.
• Automatic backups of several computers need to run unattended with nothing plugged in.

If none of these fit, a NAS becomes a device running permanently to do work a much cheaper disk handles fine.

The most expensive misunderstanding

This belongs before everything else, because it's what most often ends in lost data: a NAS is not a backup.

A NAS is somewhere to store things. A backup means a second copy somewhere separate. Moving files onto a NAS and deleting the originals isn't backing up, it's moving all the eggs into a bigger basket.

What hits a NAS hits it just as squarely as a computer: fire, theft, lightning, accidental deletion, and ransomware that reaches across the network.

The widely used rule: three copies, two kinds of media, one off-site. A NAS fills one of those three, not all of them.

RAID isn't a backup either

This is the second misunderstanding, and it follows from the first.

RAID writes data to more than one disk so the system keeps running when one fails. What it protects is availability: not the data.

• A file you delete by mistake disappears from both disks instantly.
• Ransomware takes both at once.
• Lightning that destroys the unit destroys everything inside it.

RAID reduces downtime. At home, downtime is rarely the problem, loss is. So for most homes, one large disk plus a backup elsewhere is worth more than two RAID disks with no backup.

Choosing the unit

Number of bays

Two, for nearly every home. One bay leaves no options later; four are rarely filled and add cost up front for capacity that may never be needed.

Two bays keep things open: they can mirror each other or pool their capacity, and that decision can still be changed afterwards.

Disks

Use disks actually intended to run continuously. Desktop disks are designed for a few hours a day; a NAS runs around the clock, and the difference tells on their lifespan.

If fitting two disks, it's worth avoiding an identical production batch. Two identical disks bought together tend to fail around the same time, precisely the situation you most want to avoid.

Network connection

Here is where a NAS most often disappoints for no obvious reason: it's been put on Wi-Fi.

A NAS must be cabled. It doesn't move, and its traffic is large and continuous, exactly the opposite of what suits wireless. A NAS on Wi-Fi isn't merely slow itself; it also loads the air everything else is using.

Cable choice is in the guide to choosing LAN cable, and if ports run short, the guide to choosing a network switch covers adding them.

The speed you actually get

The number printed on the disk is almost never the number you feel, because the narrowest point along the path sets the limit.

The middle row deserves attention: old cable or an old switch caps things at 100 Mbps even when both ends are gigabit, and the symptom is copying that's slow for no visible reason.

Security, and why it matters more here

A NAS holds the most valuable files in the house, and it runs twenty-four hours a day. Both make securing it more consequential than for other equipment.

• Don't expose it to the internet unless genuinely necessary. This matters most. If outside access is needed, use the manufacturer's own route rather than direct port forwarding.
• Change the default administrator password, and disable the guest account.
• Keep its software updated. A NAS is an attractive target precisely because its contents are valuable.
• Keep it off the smart-device network. The reasoning matches the guide to separating guest networks, the easiest devices to compromise are best not sharing a room with your files.

If the NAS records security cameras, the extra considerations are in the guide to CCTV camera security.

Power

A device that runs continuously needs treating as one. A sudden power cut while a NAS is writing can damage its file structure, not merely the file being written.

One small UPS is enough, and many NAS units can shut themselves down cleanly once the UPS reports the mains has gone. Details in the guide to a UPS for your router.

Heat applies just as it does to routers, give it space, and don't shut it in a closed cabinet. See the guide to router maintenance.

A NAS solves one particular problem: files that several devices need, available all the time. If you don't have that problem, an external drive handles the rest for a fraction of the cost.

And if you do use one, the two things that matter most aren't its specifications: cable it, don't use Wi-Fi, and keep a copy somewhere else. A NAS without a backup is just a bigger basket for all your eggs.

Frequently asked questions