Data Access Layer

The MSR 4 Data Access Layer manages data storage, retrieval, and caching within the system. It encompasses Key-Value storage for caching, an SQL database for storing metadata such as project details, user information, policies, and image data, and Data Storage, which serves as the backend for the registry.

Data Access Layer Elements	Description
Key Value Storage	MSR 4 Key-Value (K-V) storage, powered by Redis, provides data caching functionality and temporarily persists job metadata for the Job Service.
Database	The MSR 4 database stores essential metadata for Harbor models, including information on projects, users, roles, replication policies, tag retention policies, scanners, charts, and images. PostgreSQL is used as the database solution.
Data Storage	Multiple storage options are supported for data persistence, serving as backend storage for the OCI-compatible registry.