23 documented AWS EC2 cost inefficiencies, each with how to detect it and how to fix it.
AWS EC2CER-0327
Organizations frequently pursue aggressive Spot Instance adoption based on headline discount percentages - up to 90% off On-Demand pricing - without evaluating the effective cost per unit of work completed. While Spot pricing can deliver...
AWS EC2CER-0324
AWS compute services charge the full published On-Demand rate when no commitment-based discount - such as a Savings Plan (SP) or Reserved Instance (RI) - is in effect. On-Demand pricing provides maximum flexibility, but it is also the most...
AWS EC2CER-0108
Accelerated EC2 instance types such as `p5.48xlarge` and `p5en.48xlarge (often used for ML/AI workloads)` are eligible for Compute Savings Plans, but the discount rates offered are modest compared to more common instance families. When...
AWS EC2CER-0083
When an EC2 Mac instance is stopped or terminated, its associated dedicated host remains allocated by default. Because Mac instances run only on Dedicated Hosts (one instance per host) and the host, not the instance, is the unit of...
AWS EC2CER-0211
Multi-AZ deployment is often essential for production workloads, but its use in non-production environments (e.g., development, test, QA) offers minimal value. These environments typically do not require high availability, yet still incur...
AWS EC2CER-0151
When EC2 usage declines, shifts to different instance families, or moves to other services (e.g., containers or serverless), organizations may find that previously purchased Standard Reserved Instances or Savings Plans no longer match...
AWS EC2CER-0167
Convertible Reserved Instances provide valuable pricing flexibility - but that flexibility is often underused. When EC2 workloads shift across instance families or OS types, the original RI may no longer apply to active usage. If the RI is...
AWS EC2CER-0158
Many organizations default to Intel-based EC2 instances due to familiarity or assumptions about workload compatibility. However, AWS offers AMD and Graviton-based alternatives that often deliver significantly better price-performance for...
AWS EC2CER-0096
Non-production EC2 instances are often provisioned for daytime-only usage but remain running 24/7 out of convenience or oversight. This results in unnecessary compute charges, even if the workload is inactive for 16+ hours per day. AWS...
AWS EC2CER-0012
Many EC2 workloads - such as development environments, test jobs, stateless services, and data processing pipelines-can tolerate interruptions and do not require the reliability of On-Demand pricing. Using On-Demand instances in these...
AWS EC2CER-0088
When an EC2 instance is dedicated primarily to internet-facing traffic, regional differences in data transfer pricing can drive a substantial portion of total costs. Hosting such workloads in a region with higher egress rates leads to...
AWS EC2CER-0014
Oversized instances within Auto Scaling Groups lead to inflated baseline costs, even when scaling adjusts the number of instances dynamically. When workloads consistently use only a fraction of the available CPU, memory, or network...
AWS EC2CER-0034
An EC2 instance remains in a running state but is not actively utilized. These instances may be remnants of past projects, forgotten development environments, or temporarily created for testing and never decommissioned. If an instance...
AWS EC2CER-0087
Workloads are sometimes deployed in specific AWS regions based on legacy decisions, developer convenience, or perceived performance requirements. However, regional EC2 pricing can vary significantly, and placing instances in a suboptimal...
AWS EC2CER-0047
EC2 instances are often overprovisioned based on rough estimates, legacy patterns, or performance buffer assumptions. If an instance consistently uses only a small fraction of its provisioned CPU or memory, it likely represents an...
AWS EC2CER-0339
AWS keeps a set of older EC2 families available as previous generation instance types, including M1, M2, M3, M4, C1, C3, C4, R3, R4, I2, T1, G3, P3, P3dn and A1. They remain fully supported, so nothing forces a migration, and long-lived...
AWS EC2CER-0342
On-Demand Capacity Reservations (ODCRs) hold EC2 capacity for a specific instance type, platform, tenancy and Availability Zone. They are billed at the equivalent On-Demand rate for every reserved slot whether or not an instance is running...
AWS EC2CER-0343
EC2 Dedicated Hosts are physical servers allocated to a single account, usually to bring existing socket- or core-based licenses (such as Windows Server or SQL Server) or to meet compliance requirements. The host, not the instance, is the...
AWS EC2CER-0344
Burstable performance instances (the T family) are priced for workloads that run below a baseline CPU level most of the time. T3, T3a, T4g and T8i instances launch in unlimited mode by default, which lets them burst above the baseline for...
AWS EC2CER-0345
Image pipelines, patching workflows, backup scripts and deployment tools create Amazon Machine Images continuously, and old AMIs are rarely deregistered. An EBS-backed AMI has no charge of its own, but it keeps its backing EBS snapshots,...
AWS EC2CER-0346
SQL Server on EC2 is frequently deployed as Enterprise edition by default: it is picked from an AMI list, inherited from an on-premises build, or chosen to avoid future limits. Many of these databases never use an Enterprise-only feature....
AWS EC2CER-0347
Under Microsoft's SQL Server core licensing rules, each server running SQL Server must be licensed for a minimum of four cores, so an EC2 instance with one or two vCPUs running SQL Server under bring-your-own-license still needs four core...
AWS EC2CER-0348
SQL Server Standard and Web editions cap how much compute a single SQL Server instance can use. Standard is limited to the lesser of 4 sockets or 24 cores, which AWS expresses as 48 vCPUs on EC2, and Web is limited to the lesser of 4...