Why Plan for Disaster?
Hardware failures, accidental deletions, security breaches, and software bugs can all cause data loss. A solid disaster recovery (DR) plan ensures you can restore service quickly when things go wrong.
The 3-2-1 Backup Rule
- 3 copies of your data (original + 2 backups)
- 2 different storage media (local disk + remote/cloud)
- 1 offsite copy (different physical location)
Recovery Time Objectives
Define your acceptable downtime:
- RTO (Recovery Time Objective) — how fast you need to recover
- RPO (Recovery Point Objective) — how much data loss is acceptable
Example: RTO of 1 hour with RPO of 4 hours means you need backups at least every 4 hours and must be able to restore within 1 hour.
Essential Components to Back Up
- Database dumps (MySQL, PostgreSQL)
- Web application files (/var/www)
- Configuration files (/etc)
- SSL certificates
- Crontab entries (
crontab -l > crontab.backup) - Package list (
dpkg --get-selections > packages.list)
Recovery Procedure Template
- Provision a new server with the same OS version
- Install required packages from your package list
- Restore configuration files from backup
- Restore web application files
- Restore databases
- Verify services are running and test functionality
- Update DNS records if the IP address changed
Test Regularly
Schedule quarterly recovery drills. Spin up a test server and practice the full restore process. Document any issues and update your procedure.