Persistent data and redeployment

Three kinds of storage

• Repository files: versioned content copied into the image during build.
• Writable container layer: runtime files that may disappear when the container is replaced.
• Persistent volume or database: image-independent data retained across normal redeployment.

Use the real persistent path

Verify the actual mount path for uploads, SQLite files or generated models. Calling a folder storage does not make it persistent.

A mounted volume can hide files copied into the same image directory by a new commit. Check that an import file is actually present in the running container.

PostgreSQL persistence

A separate managed PostgreSQL data volume is independent of the application container. Redeploying only the application does not reset that database. Deleting a database or service can delete data; deletion is not redeployment.

Schema changes

Deploying code does not automatically make a database schema compatible. Manage application migrations and rollback compatibility explicitly. Persistent storage and a one-off seed/import step are separate concerns.