Instances›AWS EC2›z1d›z1d.12xlarge
Compute
vCPUs48
Memory384 GiB
Mem / vCPU8.00 GiB
ProcessorXeon Platinum 8151
Clock speed4 GHz
Architecturex86_64
Storage
Type2 × 900 GB NVMe SSD
Bandwidth19,000 Mbps
Throughput2375 MB/s
IOPS80,000
Networking
Performance25 Gigabit
Max ENIs15
IPv6Yes
GPUNone
Family sizes
z1d.large2 vCPU · 16 GiB
z1d.xlarge4 vCPU · 32 GiB
z1d.2xlarge8 vCPU · 64 GiB
z1d.3xlarge12 vCPU · 96 GiB
z1d.6xlarge24 vCPU · 192 GiB
z1d.12xlarge48 vCPU · 384 GiB
z1d.metal48 vCPU · 384 GiB
z1d.12xlarge

z1d.12xlarge is AWS's memory-optimized EC2 size at 48 vCPU and 384 GiB. In the name, "z" is high clock frequency, "1" is the generation, "d" marks local NVMe storage and "12xlarge" is the size within the z1d family. It runs on Intel Xeon Platinum 8151 at 4 GHz, and AWS introduced it in July 2018. z1d is the current generation of the z family, so there is no newer AWS size to migrate to. The closest Spot shape is mh.vs1.2xlarge at 16 vCPU, so this instance maps to 3 of them — 48 vCPU and 384 GiB across the fleet, $4.46/hr on AWS in US East (N. Virginia), from $0.063/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

z1d.12xlarge gives you 48 vCPU and 384 GiB in a single machine. The largest comparable Spot node, mh.vs1.2xlarge, is 16 vCPU and 128 GiB, so the equivalent here is 3 nodes rather than one.

Spot runs as managed Kubernetes, so a 3-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 48 cores and 384 GiB in one process, it does not.

No local diskz1d.12xlarge comes with 2 × 900 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$4.464$1.388$2.812$1.842$0.063
$4.401 savings
US Central, Chicagono AWS region$0.063
US Central, Dallasno AWS region$0.393
Hong Kong$0.063
Sydney, Australia$5.424$0.962$3.417$2.255$0.063
$5.361 savings
London, UK$5.273$0.711$3.322$2.216$0.393
$4.880 savings
US West, San Jose$5.064$0.506$3.190$2.188$0.006
$5.058 savings
US Central, Dallas 2no AWS region$0.726
When to use it
Good for
  • ●Database instances that keep the working set in RAM
  • ●Graph and search workloads with large indexes
  • ●In-memory caches such as Redis and Memcached
  • ●Workloads that fit inside 384 GiB of RAM
  • ●Jobs that want 2 × 900 GB of local NVMe scratch space
  • ●Network-heavy services — AWS rates this size at 25 Gigabit
  • ●Anything that shards cleanly across 3 nodes, which is how it maps onto Rackspace Spot
Avoid if
  • ●The working set needs more than 384 GiB of RAM
  • ●The work is single-threaded. Most of these 48 vCPU would sit idle.
  • ●GPU or FPGA acceleration is needed
  • ●CPU-bound work. You are paying for memory this workload will not use.
  • ●More than 8.00 GiB of RAM per vCPU is needed — that ratio is fixed for the whole family
z1d.12xlarge runs $3,259/mo on AWS on-demand. The 3-node equivalent on Rackspace Spot: $46/mo.
  • 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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