If your business experiences significant fluctuations and frequent peak workloads, you can enable the I/O burst feature for premium performance disks. This feature allows the disk's input/output operations per second (IOPS) to exceed its maximum limit, providing higher I/O capabilities during peak times to accommodate sudden business demands. This topic describes how to enable and disable the I/O burst feature for premium performance disks of an RDS for MySQL instance using the console and API operations.
Prerequisites
The RDS for MySQL instance must use premium performance disks.
Feature overview
After you enable the I/O burst feature for a premium performance disk, the upper limits for the IOPS and throughput of the instance increase. The differences are as follows:
After you enable the I/O burst feature for the primary node, the feature is also enabled for the secondary node. However, this feature is not automatically enabled for read-only instances. You must enable it on the product page of each read-only instance.
Scenario | Maximum IOPS | Maximum throughput (MB/s) |
I/O burst disabled |
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I/O burst enabled |
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When throughput reaches its limit, IOPS is affected, and vice versa.
The preceding formula does not apply to instances that use disks with general-purpose specifications. This is because this specification type uses shared resources and cannot guarantee maximum IOPS or maximum I/O bandwidth.
For information about the maximum IOPS and maximum I/O bandwidth of the instance types in the preceding formula, see RDS for MySQL Standard Edition (formerly X86) primary instance type list and RDS for MySQL Yitian Edition (formerly ARM) primary instance type list.
Impacts
Enabling or disabling the I/O burst feature does not cause transient connections and typically does not affect your services. In rare cases, the IOPS of the instance may fluctuate. We recommend that you perform this operation during off-peak hours.
Notes
Enabling or disabling the I/O burst feature takes several minutes. The exact duration depends on the instance usage, such as read and write traffic.
Fees
The I/O performance burst feature is free of charge until September 16, 2025 (Singapore time). Starting from September 16, 2025, you will be charged for this feature. For more information, see the Official Billing Announcement.
Billing Information
Unit price
Hourly I/O burst fee for an instance = (Total I/O burst usage of all nodes in the instance - Free quota) × Unit price
I/O burst unit price: USD 0.0015 per 10,000 I/O operations.
The I/O burst usage of premium performance disks for an RDS instance, including its primary and secondary nodes, is billed on a pay-as-you-go basis. Bills are generated on an hourly basis. I/O burst usage is measured in units of 10,000 I/O operations. Usage of less than 10,000 I/O operations is rounded up and billed as 10,000 I/O operations.
Free I/O burst quota
The free I/O burst quota for premium performance disks varies based on the RDS instance type:
Instance type | Free quota |
Basic Edition instances | 300,000 I/O operations per hour |
High-availability Edition instances | 600,000 I/O operations per hour |
Cluster Edition instances | 800,000 I/O operations per hour |
Instance I/O burst usage: The sum of the I/O burst usage of each node in the instance
RDS Edition | Instance I/O burst usage |
Basic Edition | I/O burst usage of the single node |
High-availability Edition | I/O burst usage of the primary node + I/O burst usage of the secondary node |
Cluster Edition | I/O burst usage of the primary node + I/O burst usage of all secondary nodes |
When the primary node experiences high I/O pressure and an I/O burst occurs, the secondary node also initiates a corresponding I/O burst to ensure data and service consistency. The I/O burst usage of the secondary node is nearly the same as that of the primary node.
You must enable the I/O burst feature for read-only instances separately. The billing rules are the same as those for the primary instance. If a read-only instance is a High-availability Edition instance, the fee includes the I/O burst costs for both its primary and secondary nodes.
I/O burst usage of a single node:(Portion exceeding the baseline IOPS or throughput) × Duration
Baseline I/O performance refers to the initial I/O performance of a premium performance disk, which is the maximum IOPS and throughput when the I/O burst feature is disabled.
Example scenario | A user purchased an RDS High-availability Edition instance that includes a primary node and a secondary node. The instance is configured with a 200 GB premium performance disk and has a baseline IOPS of 12,000. I/O performance burst is enabled: Within the 00:00:00 to 01:00:00 time frame, bursts occur from 00:00:00 to 00:00:27 and from 00:53:00 to 00:53:33. During these bursts, the IOPS consistently reaches 22,000. At all other times, the IOPS does not exceed the baseline value. |
Burst duration | In this example, the total burst duration is 27s + 33s = 60s. |
I/O burst usage of a single node for the hour | (22,000 - 12,000) × 60s = 600,000 |
Total I/O burst usage of the instance for the hour | 600,000 (primary) + 600,000 (secondary) = 1,200,000 |
Billing example
This example shows how to calculate the I/O burst fee for a High-availability Edition instance that has an I/O burst usage of 602,000 within one hour:
Actual I/O burst usage | 602,000 I/O operations per hour |
Free quota | 600,000 I/O operations per hour |
Usage exceeding the quota | 2,000 I/O operations |
Actual I/O burst fee | 10,000 × USD 0.0015 per 10,000 I/O operations = USD 0.0015 |
Enable or disable I/O burst
Go to the RDS Instances page. In the top navigation bar, select the region where the instance resides. Then, click the ID of the target instance.
In the section, click Configure Premium ESSD next to Premium ESSD. Then, enable or disable the I/O Performance Burst.
References
Related API operations
API | Description |
When you configure the I/O burst feature for a premium performance disk:
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