You can personalize the file storage (on the server) with the RadUploadHandler. You can see how to achieve this in our online article here.
The RadUploadHandler is designed to work with the RadUpload control. Although, it interacts with it without knowing exactly what is on the other side, they both use the same Json protocol to transfer the data. Ideally, you would be able to use another control with the upload handler, as long as it uses the same format when sending and receiving data.
For the upload control to function properly, you need an upload handler, which is hosted on the server. The upload handler itself can save the data (chunks) on the server to a local folder - using TargetFolder or PhysicalTargetFolder properties. I am not quite sure what your scenario is, but if that is not enough to upload to the cloud storage, you can create a separate service that would work with the upload handler and upload the chunks to the cloud once they arrive on the server.
the Telerik team
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