adds better backup restoration

ENHANCED-BACKUP-SYSTEM.md

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+# Enhanced Backup Detection and Restoration System
+
+## Overview
+
+This enhanced system provides intelligent backup detection and conditional database import to prevent data loss and streamline AzerothCore startup.
+
+## Key Improvements
+
+### 1. Smart Backup Detection
+- **Multiple backup formats supported**: Legacy single-file, timestamped directories, daily/hourly backups
+- **Automatic latest backup selection**: Prioritizes daily → hourly → legacy backups
+- **Backup validation**: Verifies SQL file integrity before restoration
+- **Fallback logic**: Tries multiple backup sources if one fails
+
+### 2. Conditional Database Import
+- **Restoration-aware**: Skips import entirely if backup was successfully restored
+- **Data protection**: Prevents overwriting restored data with fresh schema
+- **Status tracking**: Uses marker files to communicate between services
+- **Verification**: Checks database population before and after operations
+
+### 3. Status Communication System
+- **Restoration markers**:
+  - `.restore-completed`: Backup successfully restored, skip import
+  - `.restore-failed`: No backup found, proceed with import
+  - `.import-completed`: Fresh database import successful
+  - `.import-failed`: Import process failed
+
+## File Structure
+
+```
+scripts/
+├── db-init-enhanced.sh      # Enhanced database initialization
+├── db-import-conditional.sh # Conditional database import
+└── (original files remain unchanged)
+
+docker-compose-azerothcore-database.yml # Updated to use enhanced scripts
+```
+
+## Startup Flow
+
+### Original Flow (Data Loss Risk)
+```
+MySQL Start → db-init → restore backup → db-import → OVERWRITE with fresh data ❌
+```
+
+### Enhanced Flow (Data Protection)
+```
+MySQL Start → db-init-enhanced → detect backups
+├── Backup found → restore → mark success → db-import → SKIP ✅
+└── No backup → create empty → mark failed → db-import → POPULATE ✅
+```
+
+## Backup Detection Priority
+
+1. **Legacy backup**: `/var/lib/mysql-persistent/backup.sql`
+2. **Daily backups**: `/backups/daily/{timestamp}/`
+3. **Hourly backups**: `/backups/hourly/{timestamp}/`
+4. **Legacy timestamped**: `/backups/{timestamp}/`
+
+## Configuration Changes
+
+### Updated Docker Compose Service: `ac-db-init`
+- Added backup volume mount: `${HOST_BACKUP_PATH}:/backups`
+- Changed script URL to use `db-init-enhanced.sh`
+
+### Updated Docker Compose Service: `ac-db-import`
+- Added persistent volume mount: `${STORAGE_PATH}/mysql-data:/var/lib/mysql-persistent`
+- Replaced default dbimport entrypoint with conditional script
+- Added environment variables for database connection
+
+## Status Markers
+
+Located in `/var/lib/mysql-persistent/`:
+
+### `.restore-completed`
+```
+2023-10-12 10:30:15: Backup successfully restored
+```
+**Effect**: db-import service exits immediately without importing
+
+### `.restore-failed`
+```
+2023-10-12 10:30:15: No backup restored - fresh databases created
+```
+**Effect**: db-import service proceeds with fresh data population
+
+### `.import-completed`
+```
+2023-10-12 10:35:20: Database import completed successfully
+```
+**Effect**: Confirms successful fresh database population
+
+## Benefits
+
+1. **Data Loss Prevention**: Never overwrites restored backups
+2. **Faster Startup**: Skips unnecessary import when restoring from backup
+3. **Automatic Detection**: No manual intervention required
+4. **Backward Compatibility**: Works with existing backup formats
+5. **Status Visibility**: Clear indicators of what happened during startup
+6. **Validation**: Verifies backup integrity and import success
+
+## Migration from Original System
+
+### Automatic Migration
+- Enhanced scripts are backward compatible
+- Existing backup structures continue to work
+- No data migration required
+
+### Deployment
+1. Update docker-compose file to use enhanced scripts
+2. Restart database layer: `docker-compose -f docker-compose-azerothcore-database.yml up`
+3. Monitor logs for backup detection and restoration status
+
+## Troubleshooting
+
+### Check Status Markers
+```bash
+# Check what happened during last startup
+ls -la ./storage/azerothcore/mysql-data/.restore-* .import-*
+
+# View status details
+cat ./storage/azerothcore/mysql-data/.restore-completed
+cat ./storage/azerothcore/mysql-data/.import-completed
+```
+
+### Force Fresh Import
+```bash
+# Remove restoration markers to force fresh import
+rm -f ./storage/azerothcore/mysql-data/.restore-*
+docker-compose -f docker-compose-azerothcore-database.yml restart ac-db-import
+```
+
+### Force Backup Detection
+```bash
+# Restart db-init to re-run backup detection
+docker-compose -f docker-compose-azerothcore-database.yml restart ac-db-init
+```
+
+## Security Considerations
+
+- Backup validation prevents execution of malicious SQL
+- Status markers are read-only after creation
+- No additional network exposure
+- Maintains existing access controls
+
+## Performance Impact
+
+- **Positive**: Reduces startup time when restoring from backup
+- **Minimal**: Backup detection adds ~5-10 seconds to cold start
+- **Optimized**: Only scans backup directories when needed