AWS has announced the general availability of Amazon EC2 C7i-flex instances, which, according to the company, deliver up to 19% better price performance compared to C6i instances.
The new C7i-flex instances expand the EC2 Flex instances portfolio (including M7i-flex - general purpose compute instances), providing an easier way to achieve price-performance benefits for most compute-intensive workloads. These instances are powered by the 4th generation Intel Xeon Scalable custom processors (Sapphire Rapids), which are exclusive to AWS and offer 5% lower prices compared to C7i instances.
The C7i-flex instances, available in various sizes from large to 8xlarge, are an option for applications that don't fully utilize all compute resources. According to AWS, C7i-flex instances are well-suited for running web and application servers, databases, caches, Apache Kafka, and Elasticsearch. They are recommended for compute-intensive workloads that require larger instance sizes (up to 192 vCPUs and 384 GiB memory) or continuous high CPU usage. Storage is available via Amazon's 10Gbps Elastic Block Storage service, and networking on each instance tops out at 12.5Gb/sec throughput.
Overview of the C7i-flex instances (Source: AWS News blog post)
Amazon encourages customers to move burstier workloads to its flex instances, which can be overprovisioned due to lower chances of simultaneous high demand. For consistent CPU usage, standard C7i instances are recommended. What happens if AWS detects sustained workload on a flex instance is unclear, but it may be live migrated to a more expensive SKU. The company advises monitoring CPU utilization using CloudWatch metrics and considering non-Flex instances for heavy processing.
Comparing EC2 Ci7-flex instances to offerings on other cloud platforms is not a direct comparison. However, Azure’s F-series instances are compute-optimized and are suitable for scenarios that require faster CPUs but do not need as much memory or temporary storage per CPU core. Depending on the specific requirements of an organization's workload, they could be a match for the Amazon EC2 Ci7-flex instances.
Currently, the C7i-flex instances are available in the following AWS Regions: US West (N. California), Europe (Ireland, London, Paris, Spain, Stockholm), Canada (Central), Asia Pacific (Mumbai, Singapore), and South America (São Paulo).
