Quotas and Constraints for Amazon RDS - Amazon Relational Database Service
Quotas in Amazon RDSNaming Constraints in Amazon RDSMaximum Number of Database ConnectionsFile Size Limits in Amazon RDS

Quotas and Constraints for Amazon RDS

Following, you can find a description of the resource quotas and naming constraints for Amazon RDS.

Quotas in Amazon RDS

Each AWS account has quotas, for each AWS Region, on the number of Amazon RDS resources that can be created. After a quota for a resource has been reached, additional calls to create that resource fail with an exception.

The following table lists the resources and their quotas per AWS Region.

Resource Default Quota
Authorizations per DB security group 20
Burst balance (for instances <1 TiB) 3000 IOPS
Cross-region snapshot copy requests 5
DB instances 40
DB security groups 25
DB subnet groups 50
Event subscriptions 20
IAM roles per DB instance 5
Manual snapshots 100
Option groups 20
Parameter groups 50
Proxies 20
Read replicas per primary 5
Reserved DB instances 40
Rules per security group 20
Rules per virtual private cloud (VPC) security group 50 inbound, 50 outbound
Subnets per subnet group 20
Tags per resource 50
Total storage for all DB instances 100 TB
VPC security groups 5
Note

By default, you can have up to a total of 40 DB instances. RDS DB instances, Aurora DB instances, Amazon Neptune instances, and Amazon DocumentDB instances apply to this quota.

The following limitations apply to the Amazon RDS DB instances:

  • 10 for each SQL Server edition (Enterprise, Standard, Web, and Express) under the "license-included" model

  • 10 for Oracle under the "license-included" model

  • 40 for MySQL, MariaDB, or PostgreSQL

  • 40 for Oracle under the "bring-your-own-license" (BYOL) licensing model

If your application requires more DB instances, you can request additional DB instances by opening the Service Quotas console. In the navigation pane, choose AWS services. Choose Amazon Relational Database Service (Amazon RDS), choose a quota, and follow the directions to request a quota increase. For more information, see Requesting a Quota Increase in the Service Quotas User Guide.

Backups managed by AWS Backup are considered manual snapshots for the manual snapshots quota. For information about AWS Backup, see the AWS Backup Developer Guide.

Naming Constraints in Amazon RDS

The following table describes naming constraints in Amazon RDS.

Resource or Item Constraints

DB instance identifier

Identifiers have these naming constraints:

  • Must contain 1–63 alphanumeric characters or hyphens.

  • First character must be a letter.

  • Can't end with a hyphen or contain two consecutive hyphens.

  • Must be unique for all DB instances per AWS account, per AWS Region.

Database name

Database name constraints differ for each database engine . For more information, see the available settings when creating each DB instance.

Note

This approach doesn't apply to SQL Server. For SQL Server, you create your databases after you create your DB instance.

Master user name

Master user name constraints differ for each database engine. For more information, see the available settings when creating each DB instance.

Master password

The password for the database master user can include any printable ASCII character except /, ", @, or a space. Master password length constraints differ for each database engine. For more information, see the available settings when creating each DB instance.

DB parameter group name

These names have these constraints:

  • Must contain 1–255 alphanumeric characters.

  • First character must be a letter.

  • Hyphens are allowed, but the name cannot end with a hyphen or contain two consecutive hyphens.

DB subnet group name

These names have these constraints:

  • Must contain 1–255 characters.

  • Alphanumeric characters, spaces, hyphens, underscores, and periods are allowed.

Maximum Number of Database Connections

The maximum number of simultaneous database connections varies by the DB engine type and the memory allocation for the DB instance class. The maximum number of connections is set in the parameter group associated with the DB instance, except for Microsoft SQL Server, where it is set in the server properties for the DB instance in SQL Server Management Studio (SSMS).

Note

For Oracle, you set the maximum number of user processes and user and system sessions.

Maximum Database Connections
DB Engine Parameter Allowed Values Default Value Description
MariaDB and MySQL max_connections 1–100000 {DBInstanceClassMemory/12582880} Number of simultaneous client connections allowed
Oracle processes 80–20000 LEAST({DBInstanceClassMemory/9868951}, 20000) User processes
sessions 100–65535 – User and system sessions
PostgreSQL max_connections 6–8388607 LEAST({DBInstanceClassMemory/9531392}, 5000) Maximum number of concurrent connections
SQL Server Maximum number of concurrent connections 0–32767 0 (unlimited) Maximum number of concurrent connections
Note

You might see fewer than the maximum number of DB connections. This is to avoid potential out-of-memory issues.

File Size Limits in Amazon RDS

File size limits apply to certain Amazon RDS DB instances. For more information, see the following engine-specific limits: