Parallel sstableloader streaming would definitely be valuable.
However, this ring is currently using vnodes and I was surprised to see that a bootstrapping node only streamed from one node in the ring. My understanding was that a bootstrapping node would stream from multiple nodes in the ring.
We started with a 3 node/3 AZ, RF=3 ring. We then increased that to 6 nodes, adding one per AZ. The 4th, 5th and 6th nodes only streamed from the node in their own AZ/rack which led to the serial sstable streaming. Is this the correct behavior for the snitch? Is there an option to stream from multiple replicas across the az/rack configuration?