Retention Policies

Automatically manage backup storage by defining how long to keep backups.

Overview

Retention policies prevent unlimited storage growth by automatically deleting old backups. DBackup supports two retention modes:

Mode	Description	Best For
None	Keep all backups	Manual management
Simple	Keep last N backups	Fixed rotation
Smart (GVS)	Grandfather-Father-Son	Long-term archival

Per-Destination Retention

Retention is configured individually for each destination within a job. This means a single job can have different retention strategies per storage location.

Example

Destination	Mode	Configuration
Local NAS	Simple	Keep last 30
AWS S3	Smart (GFS)	Daily: 7, Weekly: 4, Monthly: 12
Dropbox	None	Keep all

Configuration

In the job form, expand each destination row to configure its retention:

1. Click the expand arrow on a destination
2. Select the retention mode (None / Simple / Smart)
3. Configure mode-specific settings
4. Each destination saves its retention independently

Simple Retention

Keep a fixed number of recent backups.

Configuration

Setting	Description
Keep Count	Number of backups to retain

Example

With Keep Count: 5:

• After 6th backup: 1st is deleted
• After 7th backup: 2nd is deleted
• Always maintains exactly 5 backups

Use Cases

• Development environments
• Frequent backups with short retention
• Simple rotation needs

Smart Retention (GVS)

Grandfather-Father-Son is an intelligent retention strategy that keeps:

• Recent backups (daily)
• Some older backups (weekly)
• Fewer old backups (monthly)
• Minimal very old backups (yearly)

Configuration

Setting	Description	Example
Daily	Days to keep daily backups	7
Weekly	Weeks to keep weekly backups	4
Monthly	Months to keep monthly backups	12
Yearly	Years to keep yearly backups	3

How It Works

The algorithm evaluates each backup:

1. Daily bucket: Is this one of the last N days' backups?
2. Weekly bucket: Is this the most recent backup from the last N weeks?
3. Monthly bucket: Is this the most recent backup from the last N months?
4. Yearly bucket: Is this the most recent backup from the last N years?

A backup is kept if it qualifies for any bucket.

Example Timeline

Configuration: Daily=7, Weekly=4, Monthly=12, Yearly=2

After 1 year of daily backups:

• Days 1-7: All 7 daily backups kept
• Weeks 2-4: 1 backup per week (3 more)
• Months 2-12: 1 backup per month (11 more)
• Previous year: 1 backup kept

Total: ~22 backups instead of 365!

Visual Example

Today         7 days ago    1 month ago    1 year ago
  |             |              |              |
  ▼             ▼              ▼              ▼
[■][■][■][■][■][■][■]   [■]   [■]   [■]...  [■]
 └── Daily ──┘     └ Weekly ┘  └── Monthly ──┘

Locked Backups

Prevent specific backups from being deleted:

1. Go to Storage Explorer
2. Find the backup
3. Click Lock icon

Locked backups:

• ✅ Never deleted by retention
• ✅ Don't count against limits
• ✅ Persist indefinitely

Use Cases for Locking

• Pre-migration snapshots
• Known-good backups
• Compliance requirements
• Before major changes

Configuration Guide

Conservative (Long Retention)

Daily: 14
Weekly: 8
Monthly: 24
Yearly: 5

Keeps ~50 backups over 5 years.

Moderate (Balanced)

Daily: 7
Weekly: 4
Monthly: 12
Yearly: 2

Keeps ~25 backups over 2 years.

Aggressive (Minimal)

Daily: 3
Weekly: 2
Monthly: 6
Yearly: 1

Keeps ~12 backups over 1 year.

Retention Execution

Retention runs as the final step of each backup job, applied per destination:

1. Backup upload completes for a destination
2. List all backups for this job in that specific destination
3. Read metadata (check lock status)
4. Apply that destination's retention policy
5. Delete expired backups
6. Repeat for each remaining destination

Skipped on Failure

Retention is skipped for any destination where the upload failed. This prevents deleting old backups when the new backup didn't arrive.

Compliance Considerations

GDPR

• Consider data minimization principles
• Balance retention vs. "right to erasure"
• Document retention policy

SOX/Financial

• May require 7+ years retention
• Use yearly retention setting
• Lock compliance-critical backups

HIPAA

• Minimum 6 years retention
• Consider encryption for all backups
• Document access to backups

Best Practices

Match Schedule to Retention

Schedule	Recommended Retention
Hourly	Daily: 24-48
Daily	Daily: 7-14
Weekly	Weekly: 4-8
Monthly	Monthly: 12-24

Start Conservative

Begin with longer retention, then reduce:

1. Storage is cheap
2. You can't recover deleted backups
3. Analyze needs before reducing

Test Before Production

1. Create test job with short retention
2. Verify deletion works correctly
3. Then apply to production

Monitor Storage

• Watch storage growth
• Adjust retention if growing too fast
• Use compression to reduce size

Storage Calculation

Estimate storage needs:

Storage = (Backup Size) × (Retained Backups)

Example with Smart Retention (Daily=7, Weekly=4, Monthly=12, Yearly=2):

• 100MB daily backup
• ~25 backups retained
• Storage: ~2.5GB

With compression (70% reduction):

• Storage: ~750MB

Troubleshooting

Backups Not Being Deleted

1. Verify retention is enabled on job
2. Check if backups are locked
3. View job logs for retention step
4. Ensure backup ran successfully

Too Many Backups Deleted

1. Check retention settings
2. Verify date/time on backups
3. Lock important backups
4. Increase retention values

Wrong Backups Deleted

The GVS algorithm keeps the oldest backup in each time bucket. This is intentional:

• Weekly: Keeps backup from start of week
• Monthly: Keeps backup from start of month

API Reference

Retention configuration in job:

{
  "retention": {
    "mode": "SMART",
    "simple": {
      "keepCount": 5
    },
    "smart": {
      "daily": 7,
      "weekly": 4,
      "monthly": 12,
      "yearly": 2
    }
  }
}

Next Steps

• Creating Jobs - Configure backup jobs
• Storage Explorer - Browse and lock backups
• Encryption - Secure your backups