What is a backup?
Published
A backup is keeping additional copies of your data in separate locations so you can restore it if the original is lost - through a technical failure, accidental human deletion, a ransomware attack, or physical disaster. Its real value isn't in its existence but in successful restoration from it.
The classic 3-2-1 rule
An old and durable security recommendation:
3 copies of your data (the original plus two)2 different media (not all on the same disk/server)1 copy off-site (ideally another country, or another cloud region)
The idea: one disaster does not reach three copies on two media in two places.
Backup is not sync
A common and dangerous confusion:
| Sync | Backup | |
|---|---|---|
| Deletion | Deletion is copied to the other locations immediately | The copy before deletion is retained |
| Ransomware attack | Encrypted data propagates to every copy | An older sound copy remains restorable |
| Purpose | Keeping files current across devices | Protection across time |
Sync services (Dropbox, shared Google Drive) are valuable but not a substitute for real backup with versioning through time.
The restore test - the governing point
A backup that has never been tested isn't a backup, it's a bet. A periodic test schedule is mandatory: each quarter, attempt to restore a random file from a random backup into an isolated environment. The first discovery that backups don't work must not be the day of the actual disaster.
What this means for you in a cloud accounting system
As a cloud-system user, most of the 3-2-1 responsibility sits with your provider - but you ask them about it:
- How many copies do you keep? (Daily, weekly, monthly)
- How far back do the copies go? (30 days? A year?)
- How long does restore take in a disaster? (RTO - Recovery Time Objective)
- How much data could I lose in the worst case? (RPO - Recovery Point Objective)
- Can I export my data myself? - that's your last guaranteed copy.
Wise practice: even with an excellent provider, periodic (at least monthly) export of your critical data to a medium you control. Trust does not cancel verification.
Frequently asked questions
How often should backups be taken?
Matched to change rate: active accounting data needs at least daily. Weekly means the possibility of losing a full week's transactions.
Is a copy on an external drive in the same office sufficient?
It isn't off-site - a fire or theft takes it too. The rule requires a copy in a different geographic location.
Are cloud backups more secure than local?
Major providers have security architecture hard to replicate locally; but you still verify their commitments and their terms - and a periodic export policy is in your hands.