Hardware fails, people delete things and ransomware encrypts whatever it can reach. A backup strategy is what turns those events into an inconvenience instead of a disaster. The 3-2-1 rule is a simple, widely used starting point.
Why RAID isn't enough
RAID keeps a server running when a drive fails, but every change — including mistakes and malware — is written to all drives immediately. A backup is a separate, independent copy you can go back to. See Choosing a RAID level for what RAID does protect.
The 3-2-1 rule
- 3 copies of your data — the original plus two backups.
- 2 different storage types or systems, so one failure mode can't take out every copy.
- 1 copy off-site, physically separate from the original server.
Many teams extend this with an offline or immutable copy that ransomware can't modify.
Versions and retention
A single copy that's overwritten every night will faithfully back up yesterday's corruption. Keep multiple points in time — for example daily copies for a week, weekly for a month and monthly for a year — and choose a retention policy that matches how quickly you'd notice a problem.
What to back up
- Application data, uploads and user content.
- Databases — using consistent dumps or snapshots, not a copy of live files.
- Configuration:
/etc, web-server and application configs, crontabs. - Anything needed to rebuild the server, such as deployment scripts.
Tools
Open-source tools such as restic, BorgBackup and rsync support encrypted, incremental and deduplicated backups to another server. A Storage Server makes a natural off-site target for your other servers.
Test your restores
A backup you haven't restored is a hope, not a plan. Restore a sample regularly — ideally a full server once in a while — and write down how long it took. That number is your real recovery time.
Planning backup capacity? Email sales@theclouders.com with your data size and retention needs.