Cloud Storage and Backups: The Difference Most People Miss

The most common and most expensive misunderstanding in personal data is believing that a cloud drive is a backup. A synced folder is a live mirror: a change on one device appears on all the others, immediately. That is what makes it convenient and it is exactly what makes it useless against the two most common ways people lose data, which are deletion and ransomware.

Sync versus backup

Aspect	Sync	Backup
Direction	Every change is mirrored immediately, everywhere	Periodic snapshots, one-directional
Deletion	Deleted on one device, deleted everywhere	Previous versions retained independently
Corruption or encryption	Propagates to every device	The backup is unaffected, because nothing writes to it
Ransomware	Encrypts the synced folder, which encrypts the cloud copy too	Immutable, and recoverable to a point in time
Purpose	Access files from anywhere	Survive losing the device, the account or the data

If ransomware reaches a machine with a synced folder, it encrypts files and the sync client faithfully uploads the encrypted versions. You can end up with every copy of a document destroyed within minutes, with the original one included. This is common enough that the file vendors themselves document it.

What makes a backup a backup

It is automatic. A backup you have to remember to run does not exist on the day you need it.
It retains previous versions. Point-in-time recovery is the feature that matters, not just a copy of the current state.
Nothing writes to it during normal use. This is the property that defeats ransomware. The backup tool reads; the malware cannot write.
It is somewhere else. A backup on the same disk, or in a folder inside the synced tree, protects against nothing.
It has been restored from at least once. An untested backup is a hope, not a backup. Restoring a folder of photos takes ten minutes and proves the whole chain works.

The three-two-one rule

Standard advice for a reason, and easy to satisfy as an ordinary person:

Three copies of anything you would be upset to lose

The working copy counts. So a laptop file plus a cloud copy is two.
On two different kinds of storage

Your computer's drive and a cloud service is a meaningful distinction. A second drive on the same machine is not much, since a hardware failure or a ransomware run takes both.
One copy somewhere genuinely separate

Offsite, and ideally not deletable by anything that runs on the affected device. This is what protects against fire, theft, and an account being compromised.

For most households, a workable version is: files live in one folder, that folder syncs to a cloud drive for access, and a separate backup tool takes versioned snapshots to a different service, and you restore one folder a year to confirm it works. That satisfies the rule without a second physical disk.

Choosing a service

Storage is a commodity, so the differentiators are elsewhere. The things actually worth comparing:

Version history. How far back does it go, and for how long? Fifteen days of history saves you from a mistake; a year saves you from a slow-motion problem.
E2EE — end-to-end encryption. Whether the provider can read your files. This is the single most important question for a backup, and it is also the one that varies most between products. A provider that cannot read your files is genuinely more secure against an employee, a warrant or a breach.
Recovery options. What happens if you forget the password? A provider that cannot read your data usually cannot reset it either, which is a feature and an irritation in equal measure.
Local access. Keeping a live local copy of the backup means you can restore fast and are not reliant on being online. Some services support this directly; the simplest version of it is a built-in backup tool that writes to a drive you own.
The cost at your actual size. Providers price on the smallest convenient tier, and real households drift upwards quietly. Calculate it at the size you will have in two years, not today.

Setting it up in an hour

Pick the folder that matters

One directory containing your documents, projects and anything irreplaceable. Not your whole home directory — that produces a slow, unreliable job nobody keeps running.
Set up sync for access

This is convenience, and you should treat it as convenience, not protection.
Set up a separate versioned backup

Different service, or a tool that writes to a drive you own, with versioning and a retention period set to something longer than a fortnight.
Set an exclusion for anything encrypted or huge

Back up what cannot be regenerated. Video files you still have the source of do not need three copies.
Restore something

Now, not later. Pick a folder, restore it to a different location, open three files. That is the only way to know the chain works.
Put a recurring calendar reminder on it

Once a year: check the last successful backup, confirm the backup account has two-factor on, and test a restore. Ten minutes.

Common questions

Frequently asked questions

Is having my files in the cloud enough?

It depends on whether it is a backup or a mirror, and whether the provider's version history is long enough. Cloud storage with 30 days of version history and delete protection covers accidental deletion and many ransomware cases, because the provider can restore a previous version. What it does not cover is compromise of the account itself, where the attacker can delete the versions too, and that is what a separate, possibly encrypted backup covers.

What about photo libraries on phones?

Automatic upload is fine and is a form of offsite copy, but it is still a sync: a deletion on the phone can be mirrored. Treat it as convenient duplication, and rely on your actual backup for the real protection. Make sure it is uploading originals rather than optimised versions if you care about resolution, and check the storage settings periodically — providers change default behaviour.

Should I encrypt my backup myself?

For anything genuinely sensitive, yes, and it is now much easier than it was. Look for a provider offering end-to-end encryption rather than rolling your own, since the failure mode of hand-rolled encryption is a key you cannot find. If you do encrypt yourself, write down how to decrypt it in a place that is not the same device as the backup — the most common outcome of unencrypted backups is a lock you cannot open.

How much data do I actually need?

Far more than people expect for photos and video, and almost nothing for text. A useful approach is to check what is actually large: photos and video dominate for most households, documents are small, and excluding regenerable media from a backup is a legitimate way to keep it fast and cheap without losing anything that matters.

Where to go next

These are the services referenced above. Compare them on your own terms before you sign up for anything.