Divide the data into n chunks, any k of which are able to recover the information (but with fewer than k shares, no information on the original data can be discerned). An example is Shamir's secret sharing.

This could be combined with other processors. The data payload could be split between a few cloud providers. By metadata, I mean for example an index or an ephemeral symmetric key. But the more common case could be to apply threshold secret sharing to the stream.