Amazon DocumentDB Quotas and Limits

This topic describes the resource quotas, limits, and naming constraints for Amazon DocumentDB (with MongoDB compatibility).

For certain management features, Amazon DocumentDB uses operational technology that is shared with Amazon Relational Database Service (Amazon RDS) and Amazon Neptune.

Supported Instance Types

Amazon DocumentDB supports on-demand instances and the following instance types:

• Memory Optimized:

  • R5 instance types: db.r5.large, db.r5.2xlarge, db.r5.4xlarge, db.r5.8xlarge, db.r5.12xlarge, db.r5.16xlarge db.r5.24xlarge.

  • R4 instance types: db.r4.large, db.r4.2xlarge, db.r4.4xlarge, db.r4.8xlarge, db.r4.16xlarge.

• Burstable Performance:

  • T3 instance types: db.t3.medium.

For more information on the supported instance types and their specifications, see Instance Class Specifications.

Supported Regions

Amazon DocumentDB is available in the following AWS regions:

Region Name	Region	Availability Zones (compute)
US East (Ohio)	us-east-2	3
US East (N. Virginia)	us-east-1	6
US West (Oregon)	us-west-2	4
South America (São Paulo)	sa-east-1	3
Asia Pacific (Mumbai)	ap-south-1	3
Asia Pacific (Seoul)	ap-northeast-2	4
Asia Pacific (Singapore)	ap-southeast-1	3
Asia Pacific (Sydney)	ap-southeast-2	3
Asia Pacific (Tokyo)	ap-northeast-1	3
Canada (Central)	ca-central-1	3
China (Ningxia)	cn-northwest-1	3
Europe (Frankfurt)	eu-central-1	3
Europe (Ireland)	eu-west-1	3
Europe (London)	eu-west-2	3
Europe (Paris)	eu-west-3	3
AWS GovCloud (US)	us-gov-west-1	3

Regional Quotas

For certain management features, Amazon DocumentDB uses operational technology that is shared with Amazon Relational Database Service (Amazon RDS) and Amazon Neptune. The following table contains regional limits that are shared among Amazon DocumentDB, Amazon RDS, and Neptune.

The following limits are per AWS account per region.

Resource	AWS Default Limit
Clusters	40
Cluster parameter groups	50
Event subscriptions	20
Instances	40
Manual cluster snapshots	100
Read replicas per cluster	15
Subnet groups	50
Subnets per subnet group	20
Tags per resource	50
VPC security groups per instance	5

You can use Service Quotas to request an increase for a quota, if the quota is adjustable. Some requests are automatically resolved, while others are submitted to AWS Support. You can track the status of a quota increase request that is submitted to AWS Support. Requests to increase service quotas do not receive priority support. If you have an urgent request, please contact AWS Support. For more information on Service Quotas, see What Is Service Quotas?

To request a quota increase for Amazon DocumentDB:

1. Open the Service Quotas console at https://console.aws.amazon.com/servicequotas and, if necessary, sign in.

2. In the navigation pane, choose AWS services.

3. Select Amazon DocumentDB from the list, or type Amazon DocumentDB in the search field.

4. If the quota is adjustable, you can select its radio button or its name, and then choose Request quota increase from the top right of the page.

5. For Change quota value, enter the new value. The new value must be greater than the current value.

6. Choose Request. After the request is resolved, the Applied quota value for the quota is set to the new value.

7. To view any pending or recently resolved requests, choose Dashboard from the navigation pane. For pending requests, choose the status of the request to open the request receipt. The initial status of a request is Pending. After the status changes to Quota requested, you'll see the case number with AWS Support. Choose the case number to open the ticket for your request.

Aggregation Limits

The following table describes aggregation limits in Amazon DocumentDB.

Resource	Limit
Maximum number of supported stages	500

Cluster Limits

The following table describes Amazon DocumentDB cluster limits.

Resource	Limit
Cluster size (sum of all collections and indexes)	64 TB
Collection size (sum of all collections can't exceed cluster limit) – does not include the index size	32 TB
Collections per cluster	100,000
Databases per cluster	100,000
Database size (sum of all databases can't exceed cluster limit)	64 TB
Document nesting depth	100 levels
Document size	16 MB
Index key size	2,048 bytes
Indexes per collection	64
Keys in a compound index	32
Maximum number of writes in a single batch command	100,000
Number of users per cluster	1000

Instance Limits

The following table describes Amazon DocumentDB limits per instance.

Instance Type	Instance Memory (GiB)	Connection Limit	Cursor Limit (per minute)	Open Transaction Limit (per minute)
T3.medium	4	500	30	50
R4.large	15.25	1700	450	N/A
R4.xlarge	30.5	3400	450	N/A
R4.2xlarge	61	6800	450	N/A
R4.4xlarge	122	13600	725	N/A
R4.8xlarge	288	27200	1450	N/A
R4.16xlarge	488	30000	2900	N/A
R5.large	16	1700	450	200
R5.xlarge	32	3500	450	400
R5.2xlarge	64	7100	450	800
R5.4xlarge	128	14200	760	1600
R5.8xlarge	256	28400	1520	3200
R5.12xlarge	383	30000	2280	4800
R5.16xlarge	512	30000	3040	6400
R5.24xlarge	768	30000	4560	9600

You can monitor and alarm on the per instance limits using the following the following CloudWatch metrics. For more on Amazon DocumentDB CloudWatch metrics, see Monitoring Amazon DocumentDB with CloudWatch.

Limit	CloudWatch Metrics
Instance Memory	FreeableMemory
Connections	DatabaseConnectionsMax
Cursors	DatabaseCursorsMax
Transactions	TransactionsOpenMax

Naming Constraints

The following table describes naming constraints in Amazon DocumentDB.

Resource	Default Limit
Cluster identifier	Length is [1–63] letters, numbers, or hyphens. First character must be a letter. Cannot end with a hyphen or contain two consecutive hyphens. Must be unique for all clusters (across Amazon RDS, Amazon Neptune, and Amazon DocumentDB) per AWS account, per Region.
Collection name: <col>	Length is [1–57] characters.
Database name: <db>	Length is [1–63] characters.
Fully qualified collection name: <db>.<col>	Length is [3–120] characters.
Fully qualified index name: <db>.<col>.$<index>	Length is [6–127] characters.
Index name: <col>$<index>	Length is [3–63] characters.
Instance identifier	Length is [1–63] letters, numbers, or hyphens First character must be a letter Cannot end with a hyphen or contain two consecutive hyphens Must be unique for all instances (across Amazon RDS, Amazon Neptune, and Amazon DocumentDB) per AWS account, per Region.
Master password	Length is [8-100] printable ASCII characters. Can use any printable ASCII characters except for the following: / (forward slash) " (double quotation mark) @ (at symbol)
Master user name	Length is [1-63] alphanumeric characters. First character must be a letter. Cannot be a word reserved by the database engine.
Parameter group name	Length is [1–255] alphanumeric characters. First character must be a letter. Cannot end with a hyphen or contain two consecutive hyphens.

TTL Constraints

Deletes from a TTL index are not guaranteed within a specific timeframe and are best effort. Factors like instance resource utilization, document size, and overall throughput can affect the timing of a TTL delete.