Overview of specifications quotas and usage limits - ApsaraDB RDS

ApsaraDB RDS for MySQL enforces the following limits to maintain instance stability and security.

Unless a specific version is mentioned, the limits in this topic apply to all versions.

For limits on other database engines, see:

Specifications and performance

Resource	Limit	Notes
Storage space	High-performance local disks: up to 8,000 GB<br>Standard SSDs: up to 6,000 GB<br>Enterprise SSDs (ESSDs): up to 64,000 GB	The maximum varies by instance type. See Primary instance types.
Temporary tablespace	High-performance local disks: up to 300 GB<br>Cloud disks: unlimited	Exceeding the 300 GB limit on high-performance local disks can cause frequent high-availability switches and instance breakdowns.
Connections	Up to 100,000	The maximum varies by instance type. See Primary instance types.
IOPS	High-performance local disks: up to 144,000<br>Cloud disks: see IOPS	—
Memory	High-performance local disks: up to 720 GB<br>Cloud disks: up to 768 GB	For cloud disk instances, the underlying operating system consumes approximately 500–700 MB and ApsaraDB RDS management services consume approximately 500 MB. The actual available memory is less than the specified size.
JSON column	Maximum storable data: 4 GB	—

Quotas

Quota	Limit	Adjustable
Read-only instances per primary instance	10	No
Pay-as-you-go and Serverless primary instances	200	Yes — submit a request in Quota Center
Tags per instance	20 (each tag key must be unique)	No
Instances per batch tag operation	50	No
Free backup storage — high-performance local disks	50% × purchased storage space	No
Free backup storage — cloud disks	200% × purchased storage space	No
Backup retention period	Default: 7 days. Maximum: 730 days. Backups retained beyond 730 days are converted to archive backups at a lower storage cost. See Backup storage costs.	No

The excess backup usage is calculated as: Data backup size + Log backup size - Free quota. The value is measured in GB and rounded up to the nearest integer.

Log retention periods

Log type	Retention period
Error logs	30 days
Slow query log details	7 days
Slow query log statistics	7 days
Primary/secondary switchover logs	30 days

See View error logs and slow query logs.

Naming limits

Item	Rules
Instance name	2–255 characters. Allowed: uppercase letters, lowercase letters, Chinese characters, digits, underscores (`_`), and hyphens (`-`). Must start with a letter or a Chinese character.
Account name	MySQL 8.0 or 5.7: 2–32 characters. MySQL 5.6: 2–16 characters. Allowed: lowercase letters, digits, and underscores (`_`). Must start with a lowercase letter and end with a lowercase letter or digit. Must be unique and cannot be an SQL keyword.
Database name	Up to 64 characters. Allowed: lowercase letters, digits, underscores (`_`), and hyphens (`-`). Must start with a lowercase letter and end with a lowercase letter or digit. Must be unique and cannot be an SQL keyword.
User-defined function name	Avoid reserved keywords.

Security limits

Passwords

Passwords must be 8–32 characters and contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters (!@#$%^&*()_+-=).

Network and access

Item	Limit
Default port	3306. Change it in the console if needed. See View or change endpoints and ports.
Disk encryption	Can only be enabled during instance creation. Cannot be disabled afterward. See Configure disk encryption.
Security groups per instance	Maximum 10. If an ApsaraDB RDS instance and an Elastic Compute Service (ECS) instance are in different security groups, the ECS instance cannot access the RDS instance. The security group must match the instance network type: virtual private cloud (VPC) instances can only join VPC-type security groups; classic network instances can only join classic network-type security groups. See Configure a security group.
IP whitelist groups per instance	Maximum 50. Each group supports up to 1,000 IP addresses or CIDR blocks. See Configure an IP address whitelist.
Public endpoint	Must be manually requested. See Apply for or release a public endpoint.

Account permissions

ApsaraDB RDS does not provide root or sa permissions.

Privileged accounts:

One privileged account per instance (create and manage it in the console or via API only).
A privileged account can disconnect any other account.

Standard accounts:

Create and manage standard accounts in the console, via API, or using SQL statements.
Standard accounts cannot create or manage other accounts, and cannot disconnect other accounts.
By default, a standard account can only connect to the current database. Grant permissions on specific databases in the console, or use a GRANT statement. See Modify permissions of a standard account and Account permissions.

XA_RECOVER_ADMIN permission (MySQL 8.0 only):

Only MySQL 8.0 instances support this permission.
For accounts created in the RDS console, grant it manually using the GRANT command.
Accounts created via other means (such as the CREATE USER command on a client) cannot be granted this permission.

Instance parameters:

Most parameters can be modified in the console or via API. For security and stability, some parameters cannot be modified.

Instance operation limits

Storage engines

Supported engine:

InnoDB

Unsupported engines:

Engine	Status	Details
X-Engine	New instances not supported	Convert existing X-Engine instances to InnoDB and enable storage compression to reduce storage costs.
TokuDB	Not supported since August 1, 2019	Percona no longer maintains TokuDB and many known bugs remain unfixed. See [Discontinuation] Convert TokuDB to InnoDB.
MyISAM	Not supported	Existing MyISAM tables are automatically converted to InnoDB. See Why is MyISAM not supported?
MEMORY	Not supported	MEMORY tables are automatically converted to InnoDB.

Backup and recovery

Operation	Allowed methods
Logical backup	Command line or graphical user interface (GUI)
Physical backup	RDS console or API only
Logical recovery	Command line or GUI
Physical recovery	RDS console or API only

Logging

Logging is enabled by default and cannot be disabled.
The binlog_format parameter is fixed to ROW and cannot be changed.

High availability and replication

ApsaraDB RDS for MySQL uses a primary/secondary replication architecture (except for Basic Edition instances).

High-availability series: The secondary instance is not readable.
Cluster Edition: Secondary nodes are readable.

Other limits

Item	Limit
Single table size	Up to 16 TB (OS file size limit). See Single table size limits.
Storage space — full behavior	When storage is full, the instance is automatically locked. Monitor storage usage regularly to prevent this. If the storage space of an instance is full, the instance is automatically locked. This affects its use. Regularly check the storage usage.
Instance restart	Restart in the console or via API.
Network settings (MySQL 5.5/5.6)	If the instance is in the classic network and has database proxy enabled, do not enable `net.ipv4.tcp_timestamps` in SNAT mode.
Help information	All MySQL versions include the `mysql.help_topic` schema and support the `HELP` command. In some versions, help data may not be initialized and query results may be empty. Manually import a script to populate the data.