# Storage Tier Selection > Depth-first rabbithole dossier for Storage Tier Selection; source-anchored research pack. Parent: [MongoDB Atlas Cost Optimization](https://llms-explorer.com/tree/mongodb-atlas-cost-optimization/) · 5 facets · 35 facts · page: https://llms-explorer.com/tree/storage-tier-selection/ ## Structure and components - [low] An M30 Atlas Core cluster standard replica set is configured with 8 GB RAM on each of the 3 data-bearing nodes, and Atlas Infinite clusters have the same RAM at each tier as Atlas Core clusters but differ in node count and storage layer. Sources: https://www.mongodb.com/docs/atlas/sizing-tier-selection.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` ## How it works - [low] Charges for Gen2 cluster storage capacity include the baseline minimum IOPS for that disk size, and switching from Gen1 to Gen2 may result in an IOPS rate higher than the baseline included with 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/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] MongoDB Atlas charges for storage capacity differently depending on whether the cluster default or a custom storage capacity is used; default storage cost is included in the per-hour cost, but a charge for default storage is included when the cluster is paused. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` ## Measurements and reference values - [low] MongoDB Atlas M0 (Free Tier) offers 512 MB storage with shared RAM and vCPU at no cost, M2 offers 2 GB storage starting around $9/month, and M5 offers 5 GB storage starting around $25/month. (verified as of 2026-10-15) Sources: https://www.vendr.com/marketplace/mongodb — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] AWS MongoDB Atlas tiers range from 10 GB storage, 2 GB RAM, and 2 vCPUs for $0.08/hr to 4000 GB storage, 768 GB RAM, and 96 vCPUs for $33.26/hr. (verified as of 2026-10-15) Sources: https://www.vantage.sh/blog/mongodb-cost-optimization-tips — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] If a selected cluster tier lacks sufficient RAM, such as an Azure M200 with 256 GB RAM, sharding is required. Sources: https://www.mongodb.com/docs/atlas/sizing-tier-selection.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] MongoDB Atlas M10 offers 2 GB RAM and 10 GB storage typically costing $0.08–$0.15/hour, M20 offers 4 GB RAM and 20 GB storage at $0.20–$0.40/hour, M30 offers 8 GB RAM and 40 GB storage at $0.50–$0.80/hour, and M40 offers 16 GB RAM and 80 GB storage at $1.00–$1.60/hour. (verified as of 2026-10-15) Sources: https://www.vendr.com/marketplace/mongodb — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] MongoDB Atlas M50 offers 32 GB RAM and 160 GB storage typically costing $2.00–$3.20/hour, while M60 and above provide larger instance sizes for high-throughput workloads with pricing that scales with resources. (verified as of 2026-10-15) Sources: https://www.vendr.com/marketplace/mongodb — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] MongoDB Atlas Shared clusters provide three tiers ranging from 512 MB to 5 GB, each featuring shared CPU and RAM, with costs spanning from free (M0, not recommended for production) to $25. (verified as of 2026-10-15) Sources: https://www.vantage.sh/blog/mongodb-cost-optimization-tips — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` ## Comparisons and alternatives - [low] Customizing the storage capacity (rather than changing the cluster tier) can be a disk upgrade or an instance family change, such as changing from general CPU to low-CPU. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [high] The Low CPU option in MongoDB Atlas provides instances with half the vCPUs of the General option for the same cluster tier, such as 2 vCPUs for a Low CPU M40 instance compared to 4 vCPUs for a General M40 instance, to reduce costs for memory-intensive workloads that do not require high processing power. Sources: https://www.mongodb.com/docs/atlas/customize-storage.md, https://www.mongodb.com/docs/atlas/architecture/current/scalability.md, https://www.mongodb.com/docs/atlas/architecture/current/cost-saving-config.md, https://www.vantage.sh/blog/mongodb-cost-optimization-tips, https://dev — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] If you customize storage capacity in MongoDB Atlas, the service charges for the full amount of storage rather than deducting the cost of the default storage capacity; for example, increasing a new M10 cluster from its 10 GB default to 50 GB results in a charge for 50 GB. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - Fact 116 states that general CPU instances have double the CPU of low-CPU tiers with a 20% price increase, while Fact 1 and 2 describe the Low CPU option as having half the vCPUs of the General option, implying a 50% reduction in CPU resources rather than a simple 20% price differential context. Sources: https://www.mongodb.com/docs/atlas/customize-storage.md, https://dev.to/aws-builders/so-long-documentdb-hello-mongodb-atlas-1d14 — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#disagreements` ## Facts and statements - [low] On Atlas Infinite clusters, the cluster tier fixes the storage IOPS (Input/Output Operations per Second) and storage throughput values. Sources: https://www.mongodb.com/docs/atlas/sizing-tier-selection.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] Each MongoDB Atlas cluster tier offers a default storage speed included in the per-hour cost, and the choice of cloud provider and cluster affects available storage speed customization options and costs. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] The fixed-value storage space and RAM for an NVMe cluster correspond to its cluster tier, and NVMe clusters are not compatible with independent shard scaling or multi-cloud clusters. Sources: https://www.mongodb.com/docs/atlas/nvme-storage.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] The cluster tier in MongoDB Atlas specifies the resources (memory, storage, vCPUs, and IOPS) available for each node in the cluster. Sources: https://www.mongodb.com/docs/atlas/architecture/current/high-availability.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] MongoDB Atlas provisions storage for Low CPU and General clusters in gibibytes (GiB), although the user interface displays the unit as GB. Sources: https://www.mongodb.com/docs/atlas/customize-storage.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] MongoDB Atlas imposes disk capacity limits on single replica sets, scaling up to 4 TB for higher cluster tiers. Sources: https://www.mongodb.com/docs/atlas/customize-storage.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] M30 clusters support up to 3,000 simultaneous connections, while M200 clusters support up to 128,000 simultaneous connections, though Atlas Infinite supports only M10 through M60 cluster tiers in public preview. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/atlas/sizing-tier-selection.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] The minimum cluster tier to which a cluster can scale down is a configurable setting that defaults to the current cluster tier. Sources: https://www.mongodb.com/docs/atlas/sizing-tier-selection.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] For most cluster types, storage speed can be increased from Standard to Fast or Fastest, which changes the storage type from general-purpose SSD to provisioned-IOPS SSD and affects costs. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] Gen2 Dedicated clusters have a baseline minimum IOPS based on disk storage, and Atlas charges separately for Extended Standard IOPS provisioned beyond this baseline. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] If fast disk pre-warming is enabled for an M40+ cluster hosted on AWS, Atlas may temporarily provision a higher performance AWS disk and add its cost to the regular storage costs in the monthly bill. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] Increasing storage capacity can change the maximum IOPS available with each Custom Storage Speed. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] MongoDB Atlas charges only for storage on paused clusters and does not charge for other services or data transfer. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] M30+ Dedicated clusters on AWS or Google Cloud are available in Gen1 or Gen2 cluster generations, where Gen1 clusters have different IOPS, storage, and costs than Gen2 clusters of the same class. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] NVMe clusters are supported on AWS for cluster tiers M40, M50, M60, M80, M200, and M400, and on Azure for tiers M60, M80, M200, M300, M400, and M600. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/atlas/nvme-storage.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] On AWS, NVMe storage is supported on Gen2 Dedicated clusters, but Atlas Infinite does not support locally attached NVMe SSD storage in public preview. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/atlas/nvme-storage.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] Five days after deleting the online archive, Atlas automatically deletes all files and metadata on the online archive storage, and archived data is deleted after a user-specified period ranging from 7 to 9,125 days. Sources: https://www.mongodb.com/docs/atlas/online-archive/overview.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] Scaling to a higher cluster tier improves the cluster's ability to handle traffic spikes and increases system reliability through faster response to high workloads. Sources: https://www.mongodb.com/docs/atlas/architecture/current/high-availability.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] AWS stores data on multiple devices across a minimum of three Availability Zones in a Region, Microsoft Azure uses locally redundant storage replicating data three times within a single data center, and Google Cloud spreads data across multiple zones in the region. Sources: https://www.mongodb.com/docs/atlas/architecture/current/high-availability.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] Additional MongoDB Atlas costs include storage beyond base allocation, data transfer, backup storage, and optional features like Analytics Nodes or BI Connector. Sources: https://www.vendr.com/marketplace/mongodb — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#core` - [low] M30 and higher cluster tiers are recommended for production environments, while M10 and M20 clusters may be used for low-traffic production applications but may experience degraded performance under sustained loads. Sources: https://www.mongodb.com/docs/atlas/sizing-tier-selection.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#patterns` - [low] After switching a cluster to Gen2, it is recommended to adjust storage capacity and IOPS rate independently to fit the workload and optimize costs. Sources: https://www.mongodb.com/docs/atlas/billing/cluster-configuration-costs.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/storage-tier-selection-fcda89ff7d/rabbithole-synthesis.md#patterns` ## Related concepts - Storage — is a part of Storage Tier Selection - Tier — is a part of Storage Tier Selection