Solving the MySQL Docker "Permission Denied" Error on Synology NAS: A Step-by-Step Guide

Encountering the frustrating "Permission denied" error when deploying a MySQL container on your Synology NAS? This common issue often stems from a permissions mismatch between the user inside the container and the host folders on the NAS. This article breaks down a real-world case to analyze the root cause—a UID/GID mismatch—and provides comprehensive solutions, from a quick fix to the recommended best practice, to resolve it for good.