The secret sauce here is the opportunity cost of running one's own storage at that scale. At that scale its less about sourcing the hardrives (yes its a proble

The secret sauce here is the opportunity cost of running one's own storage at that scale. At that scale its less about sourcing the hardrives (yes its a problem, but now youre a big customer so you can ask for specialised things, and a 50% discount) The big problem is the hosting, finding and building a number of datacentres local to where your customers are. Powering them, and connecting in a reliable way. But even more, you need to make a storage interface that doesn't suck. I am currently working with a homegrown S3 "like" interface. It is a massive pain in the arse as it doesn't scale[1], has an entirely new set of words to describe standard things (trying to overwrite a file? it doesn't tell you that, it just says "predicate failed") [1] large files transfer very fast, faster than s3. However all the tools are written single threaded. Add to this that each operation takes at least .7-1.5 seconds, shit gets slow very quickly. There is little to no documentation, the API is odd. in short, much as it annoys me to say this: for general purpose storage, buy over build.