Tiered storage is already here. If you're using block storage in the cloud those guys are already do all sorts of optimizations (for their costs) that include t

Tiered storage is already here. If you're using block storage in the cloud those guys are already do all sorts of optimizations (for their costs) that include tiering. And on your own desktop / own server side you can do this today on Linux with bcache or dm-cache. Works great for databases.