Instances›AWS EC2›im4gn›im4gn.8xlarge
Compute
vCPUs32
Memory128 GiB
Mem / vCPU4.00 GiB
ProcessorGraviton2 Processor
Clock speed2.5 GHz
Architecturearm64
Storage
Type2 × 7,500 GB NVMe SSD
Bandwidth20,000 Mbps
Throughput2500 MB/s
IOPS80,000
Networking
Performance50 Gigabit
Max ENIs8
IPv6Yes
GPUNone
Family sizes
im4gn.large2 vCPU · 8 GiB
im4gn.xlarge4 vCPU · 16 GiB
im4gn.2xlarge8 vCPU · 32 GiB
im4gn.4xlarge16 vCPU · 64 GiB
im4gn.8xlarge32 vCPU · 128 GiB
im4gn.16xlarge64 vCPU · 256 GiB
im4gn.8xlarge

The im4gn.8xlarge pairs 32 vCPU with 128 GiB of RAM, the 4.00 GiB-per-vCPU ratio that marks a storage-optimized instance. In the name, "4" is the generation, "gn" marks AWS Graviton (ARM) processors and enhanced networking and "8xlarge" is the size within the im4gn family. It runs on AWS Graviton2 Processor at 2.5 GHz, and AWS introduced it in November 2021. im4gn is the current generation of the im family, so there is no newer AWS size to migrate to. Spot's node ladder tops out below this size, so im4gn.8xlarge becomes 2 × gp.vs1.2xlarge (32 vCPU, 128 GiB combined), $2.91/hr on AWS in US East (N. Virginia), from $0.082/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 qualityScale-out match

im4gn.8xlarge gives you 32 vCPU and 128 GiB in a single machine. The largest comparable Spot node, gp.vs1.2xlarge, is 16 vCPU and 64 GiB, so the equivalent here is 2 nodes rather than one.

Spot runs as managed Kubernetes, so a 2-node pool is the normal way to run things rather than a workaround. If your workload already sits behind a load balancer, a queue or a scheduler, it spreads across them without changes. If it needs all 32 cores and 128 GiB in one process, it does not.

x86_64 onlyim4gn.8xlarge 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.
No local diskim4gn.8xlarge comes with 2 × 7,500 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.
Pricing by region
1 hr
RegionAWS on-demandAWS Spot1-yr Reserved3-yr ReservedRackspace SpotYou save
US East, N. Virginia$2.910$1.116$1.867$1.331$0.082
$2.828 savings
US Central, Chicagono AWS region$0.082
US Central, Dallasno AWS region$0.102
Hong Kong$0.022
Sydney, Australia$3.489$0.754$2.251$1.597$0.322
$3.167 savings
London, UK$3.377$0.383$2.178$1.540$0.442
$2.935 savings
US West, San Jose$0.302
US Central, Dallas 2no AWS region$0.002
US East, N. Virginia 2$2.910$1.116$1.867$1.331$0.302
$2.608 savings
When to use it
Good for
  • ●Elasticsearch and OpenSearch data nodes
  • ●NoSQL stores such as Cassandra, ScyllaDB and MongoDB
  • ●Data warehousing and log processing
  • ●Workloads that fit inside 128 GiB of RAM
  • ●Jobs that want 2 × 7,500 GB of local NVMe scratch space
  • ●Network-heavy services — AWS rates this size at 50 Gigabit
  • ●Anything that shards cleanly across 2 nodes, which is how it maps onto Rackspace Spot
Avoid if
  • ●The working set needs more than 128 GiB of RAM
  • ●You cannot rebuild x86-only binaries or vendor images for aarch64
  • ●More than 4.00 GiB of RAM per vCPU is needed — that ratio is fixed for the whole family
  • ●The work is single-threaded. Most of these 32 vCPU would sit idle.
  • ●GPU or FPGA acceleration is needed
  • ●Workloads that never touch local disk. The instance-store premium is wasted.
$2,125/mo on AWS on-demand against $60/mo on Rackspace Spot for the 2-node equivalent — market-priced, not list-priced.
  • Spot sells spare capacity at market prices. It is the cheapest compute on the internet.
  • Prices are set by supply and demand. You pay what the market decides.
  • Compute is delivered as fully managed Kubernetes. All infrastructure is taken care of.
  • Egress costs $0.01/GB after the free allowance. AWS charges $0.09/GB.
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