Backup
A backup is a copy of important data kept somewhere separate. It is the only assurance of recovering data after a device fault, a loss or an accidental deletion.
| In brief | The practice of keeping a copy of important data somewhere separate from the original device. |
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| Technical definition | Copying data at intervals to independent locations such as external media or the cloud, so that it can be restored when needed; the 3-2-1 rule is the common framework. |
| Everyday example | Because your phone backs its photographs up to the cloud overnight while charging, your memories can be restored to a new device even if the phone is lost. |
| Why it matters | Devices fail and go missing; a backup is the only known reliable way of not losing years of photographs and documents to a single event. |
| Common misconceptions |
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The only question to ask
There is a simple way of working out whether a backup is needed: "If this device broke right now, what would I lose?" If the answer is photographs, documents or years of accumulated work, backup is not an option but a need. Storage devices can fail sooner or later; phones get lost; the wrong key gets pressed. A backup takes the consequences of those possibilities out of the category of disaster.
The 3-2-1 rule
The classic compass for backup is the 3-2-1 rule: keep at least 3 copies of the data; hold them on at least 2 different kinds of medium (a computer plus an external disk, for example); and keep 1 copy physically somewhere else (in the cloud, for example). This rule prevents a single event — theft, fire, a disk fault — from destroying every copy at once. For a home user the practical version is usually this: the device itself, plus an external disk, plus the cloud.
Set up a routine that runs itself
The best backup is the one that does not depend on remembering. The cloud backup features of phones and the automatic backup tools of computers work quietly once they are set up. It is worth remembering that synchronisation is not a backup: syncing copies the deletion too, while a backup keeps how things were. One last suggestion: test the backup now and then. A backup you cannot restore from is not really a backup.
Related terms: Cloud Storage, Synchronisation, Storage, Encryption