Also: can someone confirm that at the moment only Swift and S3 support this kind of upload strategy?
Actually, Azure was recently added [1]. But yes, as far as I am aware only Swift and S3 beyond that have multipart support right now.
So the MultipartUploadStrategy is associated with the SequentialMultipartUploadStrategy, instead of ParallelMultipartUploadStrategy: why..?
I don't know exactly - I suspect the idea was that if you wanted jclouds to do thread management you'd use the async blobstore. You should still be able to use that for 1.6.1-incubating (ctx.getAsyncBlobStore() rather than ctx.getBlobStore()), but the method is indeed deprecated.
I'm not sure what the planned future for ParallelMultipartUploadStrategy is once the async blobstore goes away. Could you create a JIRA issue that asks for parallel multipart uploads to be supported via the S3 blobstore API in 1.7? Then we can continue the discussion there.
Hope this helps! ap [1] https://issues.apache.org/jira/browse/JCLOUDS-161
