The buffering capacity of the MindConnect devices is 500mb. In case of a power breakdown data up to 500mb is collected and after the power is restored again, the data is pushed into the MindSphere.
Are you sure the Buffer of the MindConnect Nano ist 2GB?
I think the Buffer of the MCNano and the MCIoT is only 500MB.
I looked at the Log-files and there you can see this:
2017-07-14 10:23:03.915349 Info File Buffer size: 29684.3671875KB/512000KB (5.797727966308594 %)
After a view minutes the Buffer was empty again, because the MCNano have sent the Data from the buffer to the Cloud.
Thats why I think the MCNano only have 500MB.
I just verified the information with the product management and the buffer capacity is indeed limited to 500MB. The 2GB seem to be an outdated information that slipped through until today. I just fixed it in the original post. Thanks for the heads up!