My cloud home and disconnected devices

I have disconnected all devices but my cloud home was working during night for about 3 hour , even after unpluged it from router. Disk was working quite loudly. What the explanation can be? How to avoid it in the future?

The My Cloud Home must have an internet connection to function.
Loss of internet connection will cause internal logging which results in disk writes.

There are other internal database, indexing and system cleanup processes that can also result in disk activity.

Is there any way to monitor/schedule indexing and cleanup processes?
This activity lasted more than 3 hours

Monitoring and Scheduling are not supported features of the My Cloud Home.