A reader emailed me last month with a subject line I have seen a hundred times: "I have a NAS now, so my files are backed up, right?" He had a shiny Synology DS224+ sitting on his desk, two 4TB drives in a mirror, and a genuine belief that he was done worrying about his photos.
He was not done. Not even close.
The gap between "my files live on a NAS" and "my files are actually backed up" is where most people lose data. So instead of a lecture, let me answer the exact questions beginners send me, in the order they usually send them.
Is my NAS itself a backup?
No. Your NAS is storage, and storage is not the same thing as a backup. This is the single most expensive misunderstanding I run into.
A backup is a second copy of data that lives somewhere the original problem cannot reach. If your only copy of a file sits on the NAS, and the NAS gets stolen, hit by a power surge, or wiped by a bad firmware update, that file is gone. There is no second copy to pull from.
The confusion usually comes from RAID. A two-drive mirror (RAID 1) keeps working if one drive dies, and that feels like safety. But RAID protects against one specific failure, a dead drive, and nothing else.
Is a snapshot a backup then?
A snapshot is close, but it lives on the same box, so on its own it is not enough.
Snapshots are one of my favorite features on Btrfs volumes (Synology and QNAP both offer them). They freeze the state of your files at a moment in time, and they do it almost instantly using next to no space. If ransomware encrypts your documents on Tuesday, you can roll back to Monday's snapshot in about thirty seconds.
I keep hourly snapshots for a day and daily ones for a couple of weeks on my own array. They have saved me twice from my own dumb mistakes.
But here is the catch: a snapshot sits on the same volume as the live data. If that volume dies, or the whole NAS dies, the snapshots die with it. Treat snapshots as a fast local undo button, not as your safety net.
How often should I actually back up?
Match the schedule to how much work you are willing to lose. That is the whole answer, and everything else is detail.
Ask yourself: if this data reset to yesterday morning, how much would I have to redo? For family photos that trickle in, a nightly job is plenty. For a folder where you actively work on projects all day, hourly makes more sense.
Here is roughly how I set schedules for people, depending on the data.
| Data type | Backup frequency | Why |
|---|---|---|
| Photos and media library | Nightly | Slow to change, huge, rarely edited |
| Documents and active projects | Hourly to every 4 hours | Losing a day of work actually hurts |
| System config and app data | Weekly | Changes little, quick to rebuild anyway |
| Surveillance or logs | Continuous or none | Either critical or disposable, decide upfront |
Do not overthink it. A nightly backup that actually runs beats a fancy real-time setup you never finished configuring.
Do I really need an offsite copy?
Yes, and this is the question people most want to answer with "probably not."
Think about what a single event can destroy. A house fire, a burst pipe, a burglary, or a lightning strike takes out your NAS and the USB drive sitting next to it in one shot. Two copies in the same room is really just one copy with extra steps.
An offsite copy is any copy that lives in a different building. That can be a cloud service, a drive at a relative's house, or an encrypted backup at your office. The point is physical distance from the original.
What should I use for the offsite copy?
For most home users, cloud storage is the least painful option because it runs itself once configured.
On a Synology, Hyper Backup can push encrypted backups to services like Backblaze B2, and the cost is refreshingly low. At around $6 per TB per month for B2, backing up 2TB of irreplaceable photos runs roughly $12 a month. That is cheaper than most streaming subscriptions and covers the stuff you can never recreate.
If you would rather avoid a monthly bill, the low-tech version works fine: buy two external drives, keep one at a family member's place, and swap them every few weeks. It is manual, but it costs nothing after the drives.
Whatever you pick, encrypt the offsite copy. A drive at someone else's house, or data sitting in the cloud, should be unreadable without your key.
How do I know my backups actually work?
Restore a file. Today. That is the only test that means anything.
A backup you have never restored from is a hope, not a plan. I have watched people discover, at the worst possible moment, that their backup job had been silently failing for eight months because a drive filled up or a password expired.
Pick a random file, delete it (or better, copy it somewhere), and restore it from your backup. Then do a bigger test twice a year: restore an entire folder and confirm the files open. If the restore is confusing or slow, you want to learn that on a calm Tuesday, not during an actual disaster.
What files should I prioritize?
Not everything deserves equal protection, and treating it all the same is how people end up with no working backup at all.
Sort your data into two buckets. The first is irreplaceable: photos, videos, scanned documents, anything you personally created. The second is replaceable: movies you can re-download, software installers, ripped discs. Protect the first bucket like your life depends on it, and be relaxed about the second.
- Back up first: family photos and videos, tax and legal documents, personal projects, password vaults.
- Back up if convenient: music you ripped, downloaded media, game libraries.
- Skip: temporary files, caches, anything a service will hand you again for free.
Narrowing the scope makes the whole thing cheaper and faster, which means you are far more likely to actually keep it running.
Where to go from here
If you take one thing from all this, make it this order of operations: turn on snapshots for a fast local undo, set a nightly backup to a second drive, then add one offsite copy for the files you could never recreate.
You do not need to build the perfect system this weekend. You need two copies in two places by the end of the month, with one of them tested. Do that, and you have already left most NAS owners behind.
The reader with the DS224+? He set up Hyper Backup to Backblaze that same night. Twenty minutes of work, and now his kids' baby photos exist in two places instead of one. That is the whole game.
Frequently asked questions
Is RAID the same as a backup?
No. RAID keeps your NAS running if a single drive fails, but it does nothing against accidental deletion, ransomware, theft, fire, or a fried power supply. All of those hit the array as a whole. Always pair RAID with a separate backup copy.
Can I use a USB drive plugged into the NAS as my only backup?
It is a good start but not enough on its own. A USB drive attached to the NAS is a second copy, which is better than nothing, but it sits in the same room and can be destroyed by the same fire, flood, or theft. Use it as your local backup and add one offsite copy on top.
How much does it cost to back up a NAS to the cloud?
Backblaze B2 runs about $6 per TB per month, so backing up 2TB of important files costs roughly $12 monthly. Only back up the irreplaceable data, like photos and documents, to keep the cost down. Skip movies and installers you can re-download for free.
Are Synology snapshots enough to protect my data?
Snapshots are excellent for quickly undoing deletions and rolling back ransomware, and I keep them running on my own array. But they live on the same volume as your live data, so if the NAS itself dies, the snapshots die too. Treat them as a fast local undo button, not a backup.
How often should I test my backups?
Restore a single file right after you set things up, then do a larger folder restore twice a year. Also enable email alerts so a failed job tells you immediately. The worst time to discover a broken backup is during an actual emergency.
What is the 3-2-1 backup rule in simple terms?
Keep three total copies of your data, stored on two different types of media, with at least one copy kept offsite in another building. For a home NAS that usually means the live data, a local second copy, and a cloud or remote copy. It is the single most reliable habit against permanent data loss.
