Backup & Recovery Methods
Key Takeaways
- The 3-2-1 backup rule states: maintain at least 3 copies of data, on 2 different types of media, with 1 copy stored off-site (or in the cloud).
- Full backups copy everything (slowest, most storage), incremental backups copy only changes since the last backup of any type (fastest, least storage, slowest restore), and differential backups copy all changes since the last full backup (middle ground).
- Windows backup tools include File History (continuous file backup), System Image Backup (full disk image), and System Restore (system settings only).
- Recovery Point Objective (RPO) defines the maximum acceptable data loss (how old can the backup be), while Recovery Time Objective (RTO) defines the maximum acceptable downtime.
- Cloud backup services (OneDrive, Google Drive, Backblaze, Carbonite) provide automatic off-site backup with versioning, but restore speed depends on internet bandwidth.
Last updated: March 2026
Backup & Recovery Methods
Backup Types
| Backup Type | What It Copies | Speed | Storage Used | Restore Speed |
|---|---|---|---|---|
| Full | Everything | Slowest | Most | Fastest (one backup needed) |
| Incremental | Changes since last backup (any type) | Fastest | Least | Slowest (need full + all incrementals) |
| Differential | Changes since last full backup | Medium | Medium | Medium (need full + latest differential) |
Backup Rotation Example (Weekly Schedule)
Full + Incremental Strategy:
| Day | Backup Type | Contains |
|---|---|---|
| Sunday | Full | Everything |
| Monday | Incremental | Changes since Sunday full |
| Tuesday | Incremental | Changes since Monday incremental |
| Wednesday | Incremental | Changes since Tuesday incremental |
| Thursday | Incremental | Changes since Wednesday incremental |
| Friday | Incremental | Changes since Thursday incremental |
To restore Thursday's data: You need Sunday's full + Monday's inc + Tuesday's inc + Wednesday's inc + Thursday's inc (5 backups)
Full + Differential Strategy:
| Day | Backup Type | Contains |
|---|---|---|
| Sunday | Full | Everything |
| Monday | Differential | All changes since Sunday full |
| Tuesday | Differential | All changes since Sunday full |
| Wednesday | Differential | All changes since Sunday full |
| Thursday | Differential | All changes since Sunday full |
To restore Thursday's data: You need Sunday's full + Thursday's differential (2 backups)
The 3-2-1 Backup Rule
| Rule | Meaning |
|---|---|
| 3 copies | Keep at least 3 copies of important data |
| 2 media types | Store on at least 2 different types of storage (e.g., local SSD + external HDD) |
| 1 off-site | Keep at least 1 copy off-site or in the cloud |
Example: Original data on PC (copy 1) + backup on external drive (copy 2, different media) + cloud backup (copy 3, off-site)
Windows Backup and Recovery Tools
| Tool | Purpose | Location |
|---|---|---|
| File History | Continuous backup of personal files (Documents, Desktop, etc.) | Settings > Update & Security > Backup |
| System Image Backup | Full disk image for bare-metal restoration | Control Panel > Backup and Restore (Windows 7) |
| System Restore | Restores system files and settings (not personal files) | Control Panel > Recovery |
| Reset This PC | Reinstalls Windows (keep or remove files option) | Settings > Recovery |
| Windows Recovery Environment | Boot-time recovery tools (Startup Repair, CMD, System Restore) | Boot from recovery media or interrupt boot 3 times |
| Previous Versions | Restore files from File History or shadow copies | Right-click file/folder > Properties > Previous Versions |
Recovery Concepts
RPO and RTO
| Concept | Definition | Example |
|---|---|---|
| RPO (Recovery Point Objective) | Maximum acceptable data loss measured in time | RPO of 4 hours = can lose up to 4 hours of data |
| RTO (Recovery Time Objective) | Maximum acceptable downtime | RTO of 2 hours = must be operational within 2 hours |
Image-Based Recovery
- A system image is a complete copy of the entire drive (OS, programs, settings, data)
- Allows bare-metal recovery — restore to a completely new drive
- Faster than reinstalling OS + all programs individually
- Should be created after initial setup and periodically thereafter
Cloud Backup
| Service | Type | Platform |
|---|---|---|
| OneDrive | File sync + backup | Windows, mobile |
| Google Drive | File sync + backup | Android, Chrome OS |
| iCloud | File sync + device backup | macOS, iOS |
| Backblaze | Full computer backup | Windows, macOS |
| Carbonite | Full computer backup | Windows |
Backup Best Practices
- Test your backups regularly — A backup that cannot be restored is worthless
- Automate backups — Manual backups are forgotten; schedule automatic backups
- Follow the 3-2-1 rule — Multiple copies, multiple media, off-site
- Encrypt sensitive backups — Especially off-site and cloud backups
- Document the backup plan — What is backed up, where, how often, and how to restore
- Monitor backup success — Check logs to ensure backups complete without errors
- Include system state — Back up not just data files but also OS, applications, and configurations
Test Your Knowledge
Which backup type copies ONLY the changes made since the last full backup?
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D
Test Your Knowledge
To restore Wednesday's data using a full backup from Sunday and daily incremental backups, how many backup sets do you need?
A
B
C
D
Test Your Knowledge
The 3-2-1 backup rule recommends:
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B
C
D
Test Your Knowledge
What is the Recovery Time Objective (RTO)?
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B
C
D