Modern Hyperscale data centers have an endless appetite for storage performance, capacity and density, which is why several new SSD form factors have been introduced in recent years to maximize performance and capacity.
However, Kioxia believes there is a faster and cheaper way to provide cloud customers with the solid-state storage solutions they want: wafer-level SSDs.
With capacities starting at around 50 TB using the current 3D QLC NAND, such devices could offer unbeatable performance.
SSDs at the wafer level
In short, Kioxia suggests skipping dicing, mounting, chip packaging, and mounting the SSD drive, but instead using an entire wafer with 3D NAND.
The wafer is said to be examined using Kioxia's “Super Multi-Probing Technology” to detect and deactivate faulty 3D NAND chips, and then to be attached to a pad with I / O and power connections. The whole thing should be run in parallel to achieve maximum sequential and random IOPS performance.
The current capacity of SSDs is limited by form factors and chip packaging technologies, while performance limits are defined by controllers (i.e. the number of their NAND channels and their ability to perform ECC and other necessary operations quickly and effectively) and the PCI Express interface.
At the wafer level, you can get an extreme number of NAND channels (think well beyond Microsemi's 32 channels that are common for enterprise SSDs), while a PCIe 6.0 x16 interface offers bandwidth up to 128 GB / s would deliver. IOPS are monstrous multi-channel SSDs. So think of millions of IOPS.
Shigeo Oshima, Kioxia's chief engineer, described the concept of SSDs at the wafer level in a presentation at the VLSI Symposium 2020, which means that this is not a product from the company's roadmap, but will hopefully be available soon.
However, Kioxia is currently producing 1.33 TB 96-layer 3D QLC NAND chips that measure 158.4 mm2 and deliver a write performance of up to 132 MB / s due to a quad-plane architecture. Approximately 355 such chips fit on a 300 mm wafer. Assuming a yield of approximately 90%, Toshiba will receive approximately 320 good chips or 53 TB of raw 3D QLC NAND. With future iterations, Toshiba will have even more raw 3D NAND per wafer.
A solid-state storage solution based on 300 mm 3D NAND wafers looks like a standard rack server with its own logic, power supply, cooling system and other components such as network interfaces. From a storage density point of view, such a server won't be a champion (not in a world where you can pack 100 TB in a 3.5-inch form factor), but if you need extreme performance at a relatively low price, one Device could make sense.
- Also check out our full list of the best business laptops: top devices for working from home, SMB and more
over Blocks & files