DevOps metrics are measurements used to evaluate the performance and efficiency of DevOps practices and processes.

Key categories:
1. **Velocity Metrics:**
    - Deployment frequency
    - Lead time for changes
    - Time to market

2. **Quality Metrics:**
    - Change failure rate
    - Bug detection rate
    - Test coverage

3. **Operational Metrics:**
    ```yaml
    Performance:
      - Application response time
      - Error rates
      - Resource utilization

    Reliability:
      - System uptime
      - MTTR
      - MTBF
    ```

MTTR is the average time it takes to recover from a system failure or incident.

Calculation:
```

MTTR = Total Recovery Time / Number of Incidents

```

Components of MTTR:
1. **Detection Time:**
    - Time to identify the issue
    - Monitoring alerts

2. **Response Time:**
    - Time to begin addressing the issue
    - Team mobilization

3. **Resolution Time:**
    - Time to fix the issue
    - System restoration