Data reliability engineering focuses on ensuring data quality and reliability in the modern data stack by monitoring, alerting, testing, and documenting data. It differs from other roles such as data quality engineering, data architect, and data engineering. Metaplane is a tool that helps implement best practices for data reliability engineering. The benefits of this approach include improved decision-making, increased trust in data, and faster time to resolution for data issues. Challenges include maintaining consistency across the entire data stack and managing costs and resources.