i4g.4xlarge is AWS's storage-optimized EC2 size at 16 vCPU and 128 GiB. In the name, "i" is I/O, meaning local storage, "4" is the generation, "g" marks AWS Graviton (ARM) processors and "4xlarge" is the size within the i4g family. It runs on AWS Graviton2 Processor at 2.5 GHz, and AWS introduced it in May 2023. AWS has since shipped i7i and i8g; i7i.4xlarge is the direct replacement at this size, scoring 365,234 CoreMark/s against this instance's 311,284 — roughly 17% more throughput for the same vCPU count. On Rackspace Spot the same shape is mh.vs1.2xlarge — 16 vCPU, 128 GiB, matched on both dimensions, $1.24/hr on AWS in US East (N. Virginia), from $0.021/hr on Rackspace Spot.
Match qualityx86 substitution
i4g.4xlarge is Graviton (arm64). Rackspace Spot does not have arm64 servers, so mh.vs1.2xlarge is an x86_64 substitute with similar specs.
You will need x86 builds of your container images. Most software rebuilds without changes, but anything with compiled native code needs a real rebuild rather than a retag. Speed per core also differs between the two chips, so it is worth testing before deciding how many nodes to run.
No local diski4g.4xlarge comes with 1 × 3,750 GB NVMe SSD attached to the machine. Spot nodes use network storage only, so that disk doesn't come with it. If you were using it as fast scratch space, you'd move to a persistent volume or object storage, which are slower to read.
