AMD has announced it’s using Western Digital’s Memory Extension technology to provide servers with greater effective memory capacity and so take on Optane DRAM extension technology.
The Ultrastar DC ME200 Memory Extension Drive is a NAND device available in 1TiB, 2TiB and 4TiB capacities. Its use requires no modifications to the host server’s operating system, system hardware, firmware or application stacks. The ME200 has an NVMe/PCIe interface and comes in U.2 and AIC (add-in-card) HH-HL form factors.
The ME200 is a tweaked version of WD’s Ultrastar SN200 SSD, built with planar (single layer) 15nm MLC (2bits/cell) NAND. It uses vSMP software from ScaleMP to provide replacement memory management unit (MMU) functionality and virtualises the drive to form a virtual memory pool along with the host system’s DRAM.
ScaleMP’s vSMP ServerONE software can, it says: “aggregate up to 128 EPYC-based servers into a single virtual machine. This translates to 256 EPYC processors, up to 16,384 CPUs, and with up to 512 TB of main memory.”
Western Digital says the ME200 drive improves the EPYC-based server memory-to-core ratio compared to conventional scale-out DRAM compute clusters using only DIMMs. The drive also enables lower TCO of in-memory infrastructure through consolidation.
An example; a 30-node cluster, holding 30TiB of data in memory, can be reduced to a 8-node/32TiB one with 4TiB system memory each, and with increased per-node CPU utilisation.
A 1U server can support up to 24TiB of system memory using the Ultrastar memory drive for in-memory compute clusters.
WD suggests its Ultrastar memory drive is good for in-memory database engines like SAP HANA, Oracle, IBM, and Microsoft, and scale-out memory-centric architectures like Redis, Memcached, Apache Spark and large-scale databases.
Optane persistent is storage-class memory use is restricted to Intel server processors, notably the Cascade Lake CPUs, now known as Gen 2 Xeon SPs.
The likelihood of Intel extending Optane support to AMD processors is as likely as the Moon reversing its orbital direction. Hence AMD’s working with Western Digital and ScaleMP.
Compared to the use of Optane DIMMs to expand effective memory, the ME200 costs less money, is probably simpler to implement and is available for AMD EPYC as well as X86 processors. Optane-enhanced memory servers may well go faster though.
Back in 2016 ScaleMP said its software can pool Optane SSDs and DRAM as well as NAND SSDs and DRAM. We don’t hear so much about this now.