Samsung just announced a 16 Terabyte 2.5” solid state drive. It uses NAND flash memory instead of spinning platters. (The largest drive using spinning platters are about 10TB.) It uses a new 3D architecture with 48 layers to achieve this high density.
The new device was announced last week at the Flash Memory Summit. At the summit, Samsung showed a server with 48 of these drives with a total storage capacity of 768 TB at 2 million I/O per second (typical PC drives top out at < 100,000 I/O per second…)
The cost per drive looks like it will be around $8000 – more than 20 times the cost of the cheapest storage using spinning media, but in a much smaller package. This device is clearly targeted at the enterprise server market. But, as with everything else, the price should drop as competition in this space heats up.
Here's a link with more information. http://arstechnica.com/gadgets/2015/08/samsung-unveils-2-5-inch-16tb-ssd-the-worlds-largest-hard-drive/