At FMS 2022, we got a glimpse of a CXL SSD. The Samsung Memory-Semantic SSD is a different take on technology. Instead of being a block device like a SATA, SAS, or NVMe SSD, it is instead equipped with AMD-powered CXL and addressed more like memory. During the show, Samsung had this technology demo on display.
Samsung Memory-Semantic CXL SSD at FMS 2022 Powered by AMD-Xilinx
Samsung’s display at FMS 2022 was focused on hitting the AI/ML buzzwords, but it went far beyond that. The Memory-Semantic SSD utilizes CXL instead of being addressed as a standard block device.
Here is a closer view of the EDSFF E3 drive that will be a much more common form factor in the PCIe Gen5 generation.
Many PCIe Gen5 NVMe SSD demos at FMS 2022 were using Intel Alder Lake consumer platforms to get PCIe Gen5 inexpensively. This was instead running in the Eagle Stream/ Archer City/ Emmitsburg platform that many of the CXL devices are being tested in.
Here is another look at the platform. The Intel logo is clearly visible on the riser, so we know, even with the CPU sockets being covered, that this is a Sapphire Rapids platform.
Samsung says that it can store data in this CXL SSD instead of normal DRAM or SSD storage, leading to better memory utilization with large AI models.
How this works is really interesting. Samsung is using CXL.io and CXL.mem to access the device. The CXL Consortium envisioned both LBA and load/ store access happening over CXL, and so this is a device that does both.
Digging into the diagram, we can see that this is an AMD Xilinx VM1802 which is a Versal ACAP running most of the CXL logic. There is then a Samsung PM9A3 PCIe Gen4 NVMe SSD on the back end as well as a local DRAM cache.
If this sounds a bit familiar, then perhaps the answer is something we already covered, namely the Samsung and AMD Xilinx Launch 2nd Gen SmartSSD that was also at the show.
This device takes an AMD-Xilinx Versal ACAP, a PM9A3 1.92TB M.2 device, and DRAM cache and puts it into an E3 form factor.
We asked at the show if they were indeed the same device, and we received a response that did not answer that question. Still, it makes a lot of sense if they are the same physical devices since it appears as though these two share a similar feature set.
CXL is one of those technologies that will bring about a major change to server architectures. During the show, Compute Express Link CXL 3.0 was announced. The CPUs that will launch in the next year or so will be more of CXL 1.1 generation devices.
There is a big software lift to get this all working with memory expansion devices along with NAND devices that can be used for CXL.io and CXL.mem. We expect future generations of this Samsung Memory-Semantic SSD to utilize custom ASIC controllers as the technology advances.
I’d be curious as to whether this product is a response to Optane DIMMs’ failing fortunes; whether the threat of such product helped cause those failing fortunes; or whether it’s an unrelated development of a product that just happens to also provide RAM-like access to bulk nonvolatile storage.