# Atlas auto-scaling gating by oplog window and its alerts > Source-anchored research for Atlas auto-scaling gating by oplog window and its alerts. Run status: COMPLETED. Parent: [Oplog sizing under storage auto-scaling](https://llms-explorer.com/tree/oplog-sizing-under-storage-auto-scaling/) · 3 facets · 11 facts · page: https://llms-explorer.com/tree/atlas-auto-scaling-gating-by-oplog-window-and-its-alerts/ ## How it works - Atlas provides the event condition "Auto-scaling: Disk auto-scaling didn't initiate due to insufficient oplog size" when insufficient oplog size prevents disk expansion. (medium confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/reference/alert-resolutions/atlas-autoscaling-alerts.md) - Stacktape exposes disableDiskScaling separately from minimum and maximum cluster-tier bounds in its MongoDB Atlas integration; investigate the deployed configuration when storage scaling is expected but absent. (low confidence) (verified as of 2025-12-02) — [source](https://docs.stacktape.com/3rd-party-resources/mongo-db-atlas-clusters) ## Problems, failure modes and limitations - Predictive operational-node scale-up has its own insufficient-oplog alert; predictive scaling therefore also exposes an oplog-related failure condition. (medium confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/reference/alert-resolutions/atlas-autoscaling-alerts.md) - Auto-scaling event alerts apply to every cluster in a project and cannot be scoped to individual clusters; each notification identifies the triggering cluster by name and ID. (low confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/reference/alert-resolutions/atlas-autoscaling-alerts.md) - The Atlas Kubernetes generated API reference explicitly states that both the selected tier's maximum memory and oplog size can limit storage auto-scaling; an enabled diskGB flag alone does not remove these limits. (low confidence) (verified as of 2026-10-30) — [source](https://github.com/mongodb/mongodb-atlas-kubernetes/blob/main/docs/api-docs-generated.md) ## Facts and statements - Atlas Core delays an auto-scaling event until the oplog window covers the estimated scaling time; oplog sufficiency is a prerequisite beyond merely enabling storage auto-scaling. (medium confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/cluster-autoscaling.md) - Separate insufficient-oplog event alerts identify blocked compute scale-up for operational nodes in the base tier and analytics nodes in the analytics tier. (medium confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/reference/alert-resolutions/atlas-autoscaling-alerts.md) - Operators configure auto-scaling event notifications in project alert settings and can select recipients and delivery methods; auto-scaling events can also be inspected in the project Activity Feed. (medium confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/reference/alert-resolutions/atlas-autoscaling-alerts.md) - Atlas exposes oplog monitoring independently of blocked-scaling events: the oplog-window alert thresholds approximate time retained on the primary, while replication headroom compares the sync-source window with secondary replication lag. (low confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/reference/alert-conditions.md) - The documented oplog scaling gate is edition-specific: the minimum oplog retention window does not affect Atlas Infinite auto-scaling. (low confidence) (verified as of 2026-10-14) — [source](https://www.mongodb.com/docs/atlas/cluster-autoscaling.md) - IBM MAS DevOps documents an optional Atlas cluster-health alert configuration that includes an oplog-window alert below one hour; this is an integration threshold, not evidence that Atlas always requires a one-hour window for scaling. IBM labels its Atlas provider proof-of-concept and unsuitable for production. (low confidence) (verified as of 2026-10-30) — [source](https://ibm-mas.github.io/ansible-devops/roles/mongodb/)