# Quotas and constraints for Amazon Aurora
Following, you can find a description of the resource quotas and naming constraints for Amazon Aurora.
**Topics**
+ [Quotas in Amazon Aurora](#RDS_Limits.Limits)
+ [Naming constraints in Amazon Aurora](#RDS_Limits.Constraints)
+ [Amazon Aurora size limits](#RDS_Limits.FileSize.Aurora)
## Quotas in Amazon Aurora
Each AWS account has quotas, for each AWS Region, on the number of Amazon Aurora 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.
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/CHAP_Limits.html)
**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.
If your application requires more DB instances, you can request additional DB instances by opening the [Service Quotas console](https://console.aws.amazon.com/servicequotas/home?region=us-east-1#!/dashboard). 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](https://docs.aws.amazon.com/servicequotas/latest/userguide/request-increase.html) in the *Service Quotas User Guide*.
For RDS for Oracle, you can create up to 15 read replicas per source DB instance in each Region, but we recommend limiting replicas to 5 to minimize replication lag.
Backups managed by AWS Backup are considered manual DB clustersnapshots, but don't count toward the manual cluster snapshot quota. For information about AWS Backup, see the [https://docs.aws.amazon.com/aws-backup/latest/devguide](https://docs.aws.amazon.com/aws-backup/latest/devguide).
If you use any RDS API operations and exceed the default quota for the number of calls per second, the Amazon RDS API issues an error like the following one.
ClientError: An error occurred (ThrottlingException) when calling the *API\$1name* operation: Rate exceeded.
Here, reduce the number of calls per second. The quota is meant to cover most use cases. If higher quotas are needed, you can request a quota increase by using one of the following options:
+ From the console, open the [Service Quotas console](https://us-east-1.console.aws.amazon.com/servicequotas/home/).
+ From the AWS CLI, use the [request-service-quota-increase](https://docs.aws.amazon.com/cli/latest/reference/service-quotas/request-service-quota-increase.html) AWS CLI command.
For more information, see the [https://docs.aws.amazon.com/servicequotas/latest/userguide/request-quota-increase.html](https://docs.aws.amazon.com/servicequotas/latest/userguide/request-quota-increase.html).
## Naming constraints in Amazon Aurora
The naming constraints in Amazon Aurora are as follows:
+ DB cluster identifier:
+ 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.
+ Initial database name – Database name constraints differ between Aurora MySQL and Aurora PostgreSQL. For more information, see the available settings when creating each DB cluster.
+ Master username – Master username constraints differ for each database engine. For more information, see the available settings when creating the DB cluster.
+ Master password:
+ The password for the database master user can include any printable ASCII character except `/`, `'`, `"`, `@`, or a space.
+ The password can contain the following number of printable ASCII characters depending on the DB engine:
+ Aurora MySQL: 8–41
+ Aurora PostgreSQL: 8–99
+ DB parameter group:
+ 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:
+ Must contain 1–255 characters.
+ Alphanumeric characters, spaces, hyphens, underscores, and periods are allowed.
## Amazon Aurora size limits
**Storage size limits**
Aurora cluster volume maximum size varies by engine version:
**256 TiB maximum:**
+ Aurora PostgreSQL versions:
+ 17.5 and all higher versions
+ 16.9 and higher
+ 15.13 and higher
+ Aurora MySQL version 3.10 (compatible with MySQL 8.0.42) and higher
**128 TiB maximum:**
+ All earlier Aurora PostgreSQL versions
+ All available Aurora MySQL 3 versions; Aurora MySQL version 2, versions 2.09 and higher
For more information on automatic storage scaling, see [How Aurora storage automatically resizes](Aurora.Overview.StorageReliability.md#aurora-storage-growth).
To monitor the remaining storage space, you can use the `AuroraVolumeBytesLeftTotal` metric. For more information, see [Cluster-level metrics for Amazon Aurora](Aurora.AuroraMonitoring.Metrics.md#Aurora.AuroraMySQL.Monitoring.Metrics.clusters).
**SQL table size limits**
For an Aurora MySQL DB cluster, the maximum table size is 64 tebibytes (TiB). For an Aurora PostgreSQL DB cluster, the maximum table size is 32 tebibytes (TiB). We recommend that you follow table design best practices, such as partitioning of large tables.
**Table space ID limits**
The maximum table space ID for Aurora MySQL is 2147483647. If you frequently create and drop tables, make sure to be aware of your table space IDs and plan to use logical dumps. For more information, see [Logical migration from MySQL to Amazon Aurora MySQL by using mysqldump](AuroraMySQL.Migrating.ExtMySQL.mysqldump.md).