# Common Cost Overruns > Depth-first rabbithole dossier for Common Cost Overruns; source-anchored research pack. Parent: [MongoDB Atlas Cost Optimization](https://llms-explorer.com/tree/mongodb-atlas-cost-optimization/) · 3 facets · 6 facts · page: https://llms-explorer.com/tree/common-cost-overruns/ ## How it works - [low] Atlas adds the cost of higher performance disks to regular storage costs, which may result in higher storage costs in months where Atlas provisions or replaces a node on an M40+ AWS cluster. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/common-cost-overruns-e9f3f2aaa0/rabbithole-synthesis.md#core` ## Problems, failure modes and limitations - [low] To control costs on Atlas Infinite clusters, you set a maximum storage size when you create or modify the cluster, and Atlas blocks writes when the cluster reaches that limit. Sources: https://www.mongodb.com/docs/atlas/cluster-autoscaling-storage.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/common-cost-overruns-e9f3f2aaa0/rabbithole-synthesis.md#core` ## Facts and statements - [low] If you customize the amount of storage capacity, Atlas charges for the full amount of storage and does not deduct the cost of the default storage capacity. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/common-cost-overruns-e9f3f2aaa0/rabbithole-synthesis.md#core` - [low] An underloaded server costs the customer more than necessary, while an overloaded server is bad for performance and could interfere with the scaling operation itself if it is really slammed. Sources: https://www.mongodb.com/company/blog/engineering/mongodb-predictive-auto-scaling-an-experiment — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/common-cost-overruns-e9f3f2aaa0/rabbithole-synthesis.md#core` - [low] Many teams start with larger clusters and forget to adjust as they learn their real usage patterns, leading to unnecessary costs. Sources: https://www.mongodb.com/docs/atlas/architecture/current/cost-saving-config.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/common-cost-overruns-e9f3f2aaa0/rabbithole-synthesis.md#antipatterns` - [low] Poor schema design quietly drives up costs through inefficient queries and storage bloat. Sources: https://www.mongodb.com/docs/atlas/architecture/current/cost-saving-config.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/common-cost-overruns-e9f3f2aaa0/rabbithole-synthesis.md#antipatterns` ## Related concepts - Cost — is a part of Common Cost Overruns