The c5d.4xlarge pairs 16 vCPU with 32 GiB of RAM, the 2.00 GiB-per-vCPU ratio that marks a compute-optimized instance. In the name, "c" stands for compute, "5" is the generation, "d" marks local NVMe storage and "4xlarge" is the size within the c5d family. It runs on Intel Xeon Platinum 8124M at 3.4 GHz, and AWS introduced it in May 2018. AWS has since shipped c6i, c7i, c8i and c9g; c6i.4xlarge is the direct replacement at this size, scoring 276,865 CoreMark/s against this instance's 250,460 — roughly 11% more throughput for the same vCPU count. ch.vs1.2xlarge on Rackspace Spot lines up one-for-one: 16 vCPU and 32 GiB, about 95% below the US East (N. Virginia) on-demand rate.
Match qualityNo local disk
c5d.4xlarge comes with 1 × 400 GB NVMe SSD attached to the machine. Rackspace Spot nodes use network storage only, so that disk does not come with it.
If you were using the local disk as fast scratch space — temporary files, a local cache, an index — you will need a persistent volume or object storage instead, and both are slower to read. If it was just extra space you never depended on, nothing changes.
