# Phase C: Backend Core Domains - Progress Report

## Status: In Progress (Core Components Complete)

### ✅ Completed Components

#### 1. Database Schema (Migration 002)
- **File**: `backend/internal/common/database/migrations/002_storage_and_tape_schema.sql`
- **Tables Created**:
  - `disk_repositories` - Disk-based backup repositories
  - `physical_disks` - Physical disk inventory
  - `volume_groups` - LVM volume groups
  - `scst_targets` - SCST iSCSI targets
  - `scst_luns` - LUN mappings
  - `scst_initiator_groups` - Initiator groups
  - `scst_initiators` - iSCSI initiators
  - `physical_tape_libraries` - Physical tape library metadata
  - `physical_tape_drives` - Physical tape drives
  - `physical_tape_slots` - Tape slot inventory
  - `virtual_tape_libraries` - Virtual tape library metadata
  - `virtual_tape_drives` - Virtual tape drives
  - `virtual_tapes` - Virtual tape inventory

#### 2. Storage Component ✅
- **Location**: `backend/internal/storage/`
- **Features**:
  - **Disk Discovery** (`disk.go`):
    - Physical disk detection via `lsblk`
    - Disk information via `udevadm`
    - Health status detection
    - Database synchronization
  - **LVM Management** (`lvm.go`):
    - Volume group listing
    - Repository creation (logical volumes)
    - XFS filesystem creation
    - Repository listing and retrieval
    - Usage monitoring
    - Repository deletion
  - **API Handler** (`handler.go`):
    - `GET /api/v1/storage/disks` - List physical disks
    - `POST /api/v1/storage/disks/sync` - Sync disks to database (async)
    - `GET /api/v1/storage/volume-groups` - List volume groups
    - `GET /api/v1/storage/repositories` - List repositories
    - `GET /api/v1/storage/repositories/:id` - Get repository
    - `POST /api/v1/storage/repositories` - Create repository
    - `DELETE /api/v1/storage/repositories/:id` - Delete repository

#### 3. SCST Integration ✅
- **Location**: `backend/internal/scst/`
- **Features**:
  - **SCST Service** (`service.go`):
    - Target creation and management
    - LUN mapping (device to LUN)
    - Initiator ACL management
    - Single initiator enforcement for tape targets
    - Handler detection
    - Configuration persistence
  - **API Handler** (`handler.go`):
    - `GET /api/v1/scst/targets` - List all targets
    - `GET /api/v1/scst/targets/:id` - Get target with LUNs
    - `POST /api/v1/scst/targets` - Create new target
    - `POST /api/v1/scst/targets/:id/luns` - Add LUN to target
    - `POST /api/v1/scst/targets/:id/initiators` - Add initiator
    - `POST /api/v1/scst/config/apply` - Apply SCST configuration (async)
    - `GET /api/v1/scst/handlers` - List available handlers

#### 4. System Management ✅
- **Location**: `backend/internal/system/`
- **Features**:
  - **System Service** (`service.go`):
    - Systemd service status retrieval
    - Service restart
    - Journald log retrieval
    - Support bundle generation
  - **API Handler** (`handler.go`):
    - `GET /api/v1/system/services` - List all services
    - `GET /api/v1/system/services/:name` - Get service status
    - `POST /api/v1/system/services/:name/restart` - Restart service
    - `GET /api/v1/system/services/:name/logs` - Get service logs
    - `POST /api/v1/system/support-bundle` - Generate support bundle (async)

### 🔄 In Progress / Pending

#### 5. Physical Tape Bridge (Pending)
- **Requirements** (SRS-02):
  - Tape library discovery (changer + drives)
  - Slot inventory and barcode handling
  - Load/unload operations
  - iSCSI export via SCST
- **Status**: Database schema ready, implementation pending

#### 6. Virtual Tape Library (Pending)
- **Requirements** (SRS-02):
  - MHVTL integration
  - Virtual tape management
  - Tape image storage
  - iSCSI export via SCST
- **Status**: Database schema ready, implementation pending

#### 7. Enhanced Monitoring (Pending)
- **Requirements** (SRS-05):
  - Enhanced health checks
  - Alerting engine
  - Metrics collection
- **Status**: Basic health check exists, alerting engine pending

### API Endpoints Summary

#### Storage Endpoints
```
GET    /api/v1/storage/disks
POST   /api/v1/storage/disks/sync
GET    /api/v1/storage/volume-groups
GET    /api/v1/storage/repositories
GET    /api/v1/storage/repositories/:id
POST   /api/v1/storage/repositories
DELETE /api/v1/storage/repositories/:id
```

#### SCST Endpoints
```
GET    /api/v1/scst/targets
GET    /api/v1/scst/targets/:id
POST   /api/v1/scst/targets
POST   /api/v1/scst/targets/:id/luns
POST   /api/v1/scst/targets/:id/initiators
POST   /api/v1/scst/config/apply
GET    /api/v1/scst/handlers
```

#### System Management Endpoints
```
GET    /api/v1/system/services
GET    /api/v1/system/services/:name
POST   /api/v1/system/services/:name/restart
GET    /api/v1/system/services/:name/logs
POST   /api/v1/system/support-bundle
```

### Architecture Highlights

1. **Clean Separation**: Each domain has its own service and handler
2. **Async Operations**: Long-running operations use task engine
3. **SCST Integration**: Direct SCST command execution with database persistence
4. **Error Handling**: Comprehensive error handling with rollback support
5. **Audit Logging**: All mutating operations are audited (via middleware)

### Next Steps

1. **Physical Tape Bridge Implementation**:
   - Implement `tape_physical/service.go` for discovery and operations
   - Implement `tape_physical/handler.go` for API endpoints
   - Add tape endpoints to router

2. **Virtual Tape Library Implementation**:
   - Implement `tape_vtl/service.go` for MHVTL integration
   - Implement `tape_vtl/handler.go` for API endpoints
   - Add VTL endpoints to router

3. **Enhanced Monitoring**:
   - Implement alerting engine
   - Add metrics collection
   - Enhance health checks

### Testing Recommendations

1. **Unit Tests**: Test each service independently
2. **Integration Tests**: Test SCST operations with mock commands
3. **E2E Tests**: Test full workflows (create repo → export via SCST)

### Known Limitations

1. **SCST Commands**: Currently uses direct `scstadmin` commands - may need abstraction for different SCST builds
2. **Error Recovery**: Some operations may need better rollback mechanisms
3. **Concurrency**: Need to ensure thread-safety for SCST operations
4. **Validation**: Additional input validation needed for some endpoints

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**Last Updated**: Phase C - Core Components Complete
**Next Milestone**: Physical and Virtual Tape Library Implementation