The r6g.metal is a memory-optimized AWS EC2 instance: 64 vCPU and 512 GiB of memory, 8.00 GiB per vCPU. In the name, "r" stands for RAM, "6" is the generation, "g" marks AWS Graviton (ARM) processors and "metal" is the size within the r6g family. It runs on AWS Graviton2 Processor at 2.5 GHz, and AWS introduced it in June 2020. AWS has since shipped r7g, r8g and r9g; r7g.metal is the direct replacement at this size, scoring 1,531,009 CoreMark/s against this instance's 1,222,229 — roughly 25% more throughput for the same vCPU count. No single Spot node covers 64 vCPU and 512 GiB, so the equivalent is a fleet: 4 × mh.vs1.2xlarge, 64 vCPU and 512 GiB in total, $3.23/hr on AWS in US East (N. Virginia), from $0.084/hr on Rackspace Spot. Spot delivers compute as managed Kubernetes, so a node pool of that size is the native shape of the answer rather than a workaround — provided the workload scales horizontally.
Match qualityVirtualised, not bare metal
r6g.metal is a full physical server — no virtualisation layer in the way, direct access to the hardware, and a socket count that licensing can verify.
Rackspace Spot no longer sells bare metal; everything in the catalog is a virtual machine. You get the same cores and memory (4 × mh.vs1.2xlarge, 64 vCPU, 512 GiB), but not the dedicated hardware. If you picked r6g.metal because you needed the real machine — nested virtualisation, per-socket licensing, low-level profiling — this is not a replacement at any price. If you picked it because it is the biggest r6g, it is the same compute for a lot less.
Runs as a fleetNo single Spot node has 64 vCPU; the largest comparable one has 16. So this runs as 4 nodes. That works if your workload already spreads across machines, and doesn't if one process needs all the cores together.
x86_64 onlyr6g.metal is Graviton (arm64) and Rackspace Spot has no arm64 nodes, so you'd be moving to x86. You'll need x86 builds of your images, and per-core speed differs between the chips — worth testing before you decide how many nodes to run.
