Here is the article on medium.com written by Samsung architect.
Here are highlights about my favorite content:
I will add highlights later. I need to spend more time to learn this topic.
What will happen when the client is offline?
A client component, Watcher, will observe client-side folders. If any change occurs by the user, it will notify the Index Controller(another client component) about the action of the user. It will also monitor if any change is happening on other clients(devices), which are broadcasted by the Notification server.
When the Metadata service receives an update/upload request, it needs to check with the metadata DB for consistency and then proceed with the update. After that, a notification will be sent to all subscribed devices to report the file update.