Cluster Configuration Costs

Storage Capacity

Atlas charges for storage capacity differently depending on whether you use the cluster default or specify a custom storage capacity.

• If you use the default storage capacity, Atlas includes its cost in the cluster's per-hour cost.
• If you customize the amount of storage capacity, Atlas charges for the full amount of storage. Atlas doesn't deduct the cost of the default storage capacity. This change can be a disk upgrade or a instance family change such as changing from general CPU to low-CPU.

Custom Storage Speed

Atlas measures storage speed as maximum IOPS. Each Atlas cluster tier offers a default storage speed that is included in the cluster's per-hour cost. The choice of cloud service provider and cluster affects the available storage speed customization options, as well as the cost of selecting a custom storage speed.

Cluster Auto-Scaling

To help minimize cluster costs while retaining the flexibility to easily scale your cluster, you can enable Cluster Auto-Scaling. With auto-scaling, your cluster automatically scales its tier, storage capacity, or both in response to cluster usage. Auto-scaling reduces the need to manually optimize your cluster to adapt to your current workload.

Legacy Backups

The backup cost for legacy backups is calculated per GB per month. The monthly rate is annualized and then divided by 365 to arrive at a Daily Backup Rate per GB. The first 1 GB of backup data is free.

Monthly backup costs are primarily based on the size per-gigabyte of the data to back up. This size is roughly equivalent to the uncompressed size of all documents and all indexes for all the databases backed up.

To retrieve the size in gigabyte of the documents and indexes for a given database, you can issue the db.stats() method and sum the dataSize and indexSize fields.

db.stats(1024*1024*1024).dataSize + db.stats(1024*1024*1024).indexSize

The rate is based on your having 28 snapshots at steady state:

• The six-hour snapshots are kept for two days;
• The daily snapshots for one week,
• The weekly snapshots for one month,
• The monthly for one year.

Adding that up, you get 8 + 5 + 3 + 12 = 28 snapshots. We adjust the backup rate daily based on the following formula:

backupRatePerMonth = $1.25 + snapshotAtSteadyState/28 × $1.25

Changing the snapshot frequency or retention period affects the base rate per GB. See Snapshot Schedule for more information.

Cloud Backups

Atlas takes 31 snapshots for Cloud Backup each month by default. You can change the backup policy if needed. In most cases, a new snapshot saves only the data that changed after your most recent snapshot.

Atlas takes one snapshot per shard. It takes the first snapshot in full and takes incremental snapshots afterward. Atlas can take more than one full snapshot per shard in certain cases. These cases include when:

• Snapshot taken on a different node from the previous one due to failover.
• Storage volume of a node changes.
• Region priority changes for a multi-region cluster. This would set a different node as the one that creates snapshots. If Atlas deems the selected node as unhealthy, it tries to snapshot the next node that it favors.

Atlas can bill backup as high as the total storage capacity of the volume. This depends upon how the cloud provider stores the volume snapshots.

If the existing snapshot storage volume becomes invalid, Atlas creates a new snapshot storage volume in the same region as the cluster's current backup node and takes a full-copy snapshot. Atlas continues using that backup node and its cloud provider region for snapshots and snapshot storage. This may result in a higher invoice for the few days required to re-establish incremental snapshots.

To learn more about how Atlas manages snapshot storage, see Back Up Your Database Deployment.

When restoring a cluster using a manual download via HTTPS, Atlas also charges for each hour that the download link remains active. To contact MongoDB Support for more information, click Support at the top of any page.

Continuous Cloud Backups

Cluster owners may enable Continuous Cloud Backup restores from Cloud Backups. PIT backups are billed based on the disk space occupied by an internal oplog, combined with the cloud backup snapshot size.

You can configure PIT backups to cover a window of time that you specify. Longer backup windows result in larger oplogs and higher backup costs.

Atlas takes 51 snapshots for Continuous Cloud Backup each month by default. You can change the backup policy if needed. In most cases, a new snapshot saves only the data that changed after your most recent snapshot.

Continuous Cloud Backups support incremental snapshots, where a new snapshot saves only the data that changed after your most recent snapshot. For example, a cluster with 10 GB of data and 3 snapshots may require less than 30 GB of total snapshot storage depending on how data changed between snapshots.

To compute the cost for Continuous Cloud Backups, Atlas obtains the raw metric data from the cloud providers and calculates the total size of all snapshots based on the region where it stores the snapshot and the amount of storage used per month:

Lowering the Monthly Rate