Backing Up Data Properly

What a backup is not

A synchronised cloud folder is not a backup. If a file is deleted or corrupted, the change synchronises everywhere.

A second copy on the same drive is not a backup, since drive failure loses both.

A copy on an external drive kept beside the computer protects against drive failure and not against theft, fire or flood.

The standard approach

Three copies of the data, on two different types of media, with one copy stored elsewhere.

In practice for a household: the working copy on the computer, an automated copy to an external drive, and a copy in cloud storage or on a drive kept at another location.

Version history matters, since it protects against corruption and accidental changes that a simple copy would overwrite.

Setting it up

Use the automated backup software built into your operating system, which handles scheduling and versioning without effort.

Encrypt backups, particularly any stored elsewhere or in the cloud, since a lost backup drive is a data breach.

For cloud storage, understand the difference between synchronisation and backup, and enable version history and deleted-file retention.

The part everyone skips

Test the restore. A backup that has never been restored from is an assumption rather than a backup.

Restore a few files periodically and confirm they open correctly.

Check that the backup is actually running, since failures are frequently silent.

What to prioritise

Irreplaceable data first: photographs, documents, correspondence, creative work, financial records.

Software and operating systems are reinstallable and matter less.

Password manager data, which if lost locks you out of everything.

Two-factor authentication recovery codes, which should be stored securely offline.

Phones

Phone photographs are the most commonly lost data, and phone backup is frequently partial or full-storage-blocked.