One thing to add.. the version that blackblaze used direct cables the reason was that the backplanes they were using where the most unreliable part. this is so

One thing to add.. the version that blackblaze used direct cables the reason was that the backplanes they were using where the most unreliable part. this is something you can handle when all the servers are in your own DC like in blackblaze case. For netflix that need to built the server and ship it to someone else it makes more sense to go with direct cables as it would be more reliable and a cable problem would only affect a single driver, while the backplane will take 5 drivers out. also an regular sata cable is a easier part to source then a specific backplane..