The i3.xlarge pairs 4 vCPU with 30.5 GiB of RAM, the 7.63 GiB-per-vCPU ratio that marks a storage-optimized instance. In the name, "i" is I/O, meaning local storage, "3" is the generation and "xlarge" is the size within the i3 family. It runs on Intel Xeon E5-2686 v4 (Broadwell) at 2.3 GHz, and AWS introduced it in November 2016. AWS has since shipped i4i, i7i and i8g; i4i.xlarge is the direct replacement at this size, scoring 66,786 CoreMark/s against this instance's 52,722 — roughly 27% more throughput for the same vCPU count. mh.vs1.large on Rackspace Spot lines up one-for-one: 4 vCPU and 32 GiB, about 93% below the US East (N. Virginia) on-demand rate.
Match qualityNo local disk
i3.xlarge comes with 1 × 950 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.
