Due to the I/O load (i.e. low latency) we require, it's not recommended to have the historic data reside on a network storage, let alone on a cloud storage. Feel free to have the files backed up to a cloud provider of your choice, though :)
Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.