# Compute Auto-Scaling Disabled or Bounded at Launch Tier on MongoDB Atlas Clusters Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/compute-auto-scaling-disabled-or-bounded-at-launch-tier-on-mongodb-atlas-clusters Atlas compute auto-scaling moves a dedicated cluster between a minimum and maximum tier based on sustained CPU and memory usage, so clusters with daily... By: PointFive Updated: 2026-09-28 [Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) The short version Atlas compute auto-scaling moves a dedicated cluster between a minimum and maximum tier based on sustained CPU and memory usage, so clusters with daily or weekly load cycles can run on a smaller tier outside their peaks. PointFive Research Cloud cost research at PointFive MongoDB Atlas service [MongoDB Atlas](https://www.pointfive.co/efficiency-hub/cloud-services/mongodb-atlas) Category [Databases](https://www.pointfive.co/efficiency-hub/service-category/databases) Reference CER-0532 Type Inefficient Configuration ## Explanation Why the waste happens and who it affects. In the Atlas UI, auto-scaling and scale-down are enabled by default for eligible clusters. Through the Atlas Administration API, auto-scaling is not selected by default and must be enabled explicitly, so clusters created by scripts, Terraform or other infrastructure-as-code often have it off and stay at their launch tier permanently. Even where auto-scaling is on, two settings limit its effect on cost. Scale-down can be disabled, in which case a cluster that scales up for a spike never comes back down. And the UI sets the minimum cluster size to the current tier by default, so a cluster launched at a generous tier can scale up but never below where it started. MongoDB recommends enabling compute and storage auto-scaling for staging and production and bounding it with minimum and maximum sizes to control cost; its guidance for development and test is the opposite - leave auto-scaling off there to avoid growth in non-production spend. ## Billing model The pricing dimensions that drive this cost. Current tier rate Each data-bearing node is billed per hour at whatever tier the cluster is on, so time spent at a higher tier than needed is paid in full Reactive scale-down Happens only when all nodes have Normalized System CPU below 45% and projected memory below 60% at the lower tier over the last 10 minutes and 4 hours, at most once per 24 hours Tier bounds MinInstanceSize and maxInstanceSize limit how far auto-scaling can move the cluster; the UI defaults the minimum to the current tier ## How to detect 4 checks to find it in your estate. - List clusters with the Administration API or Terraform state and check replicationSpecs\[n\].regionConfigs\[m\].autoScaling.compute: flag enabled = false and scaleDownEnabled = false on staging and production clusters - Flag clusters where minInstanceSize equals the current tier, which prevents any scale-down below the launch size - Compare the tier history in the cluster's activity feed with its Normalized System CPU and System Memory metrics; clusters with clear daily or weekly cycles whose tier never changes are candidates - Check eligibility: reactive auto-scaling applies to General and Low-CPU class clusters of M10 and above, not Local NVMe SSD clusters, so flag ineligible clusters for manual review instead ## How to fix 5 ways to remove the waste. - Enable compute auto-scaling with scaleDownEnabled = true on staging and production clusters, setting minInstanceSize and maxInstanceSize explicitly in API calls and Terraform modules so new clusters do not start with it off - Lower minInstanceSize to the smallest tier that meets off-peak load and latency needs, so Atlas can scale down outside peaks; keep maxInstanceSize as a cost ceiling - Keep predictive auto-scaling enabled where eligible (M30 and above, General or Low-CPU class, active for at least two weeks) so scale-ups for predictable cycles happen before load arrives rather than by oversizing the minimum - Leave compute auto-scaling off on development and test clusters, as MongoDB recommends, and size them manually at a small tier - Review the settings after major workload changes, since scale-down waits 24 hours after the last scale-down, provisioning or unpause ## Documentation Vendor references for pricing and configuration. - [Configure Auto-Scaling mongodb.com](https://www.mongodb.com/docs/atlas/cluster-autoscaling/) - [Guidance for Atlas Scalability mongodb.com](https://www.mongodb.com/docs/atlas/architecture/current/scalability/) - [Billing Breakdown and Optimization mongodb.com](https://www.mongodb.com/docs/atlas/billing/billing-breakdown-optimization/) - [Update One Cluster in One Project mongodb.com](https://www.mongodb.com/docs/api/doc/atlas-admin-api-v2/2025-03-12/operation/operation-updategroupcluster) - [Cluster Configuration Costs mongodb.com](https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs/) ## Related inefficiencies [Browse the library](https://www.pointfive.co/efficiency-hub) - MongoDB Atlas CER-0326 ### [Continuous Backup Enabled on Non-Production MongoDB Atlas Clusters](https://www.pointfive.co/efficiency-hub/inefficiencies/continuous-backup-enabled-on-non-production-mongodb-atlas-clusters) MongoDB Atlas offers two backup mechanisms for dedicated clusters: Cloud Backups (scheduled snapshots using the underlying cloud provider's native snapshot functionality) and Continuous Cloud Backup, which adds point-in-time recovery by... Databases - MongoDB Atlas CER-0531 ### [Overprovisioned MongoDB Atlas Cluster Tier](https://www.pointfive.co/efficiency-hub/inefficiencies/overprovisioned-mongodb-atlas-cluster-tier) A dedicated MongoDB Atlas cluster is billed per hour for each data-bearing node at the rate of its cluster tier (M10, M30, M50 and so on), and the tier fixes the node's RAM, CPU, default storage and storage speed. A replica set pays for... Databases - MongoDB Atlas CER-0534 ### [Non-Production MongoDB Atlas Clusters Running When Not in Use](https://www.pointfive.co/efficiency-hub/inefficiencies/non-production-mongodb-atlas-clusters-running-when-not-in-use) Dedicated Atlas clusters are billed per hour for every data-bearing node whether or not any application is connected. Development, test, QA and demo clusters are typically used during working hours or for the length of a project, yet they... Databases --- Source: the public page above. Product screenshots and illustrative interfaces are examples, not live customer data.