If your business experiences significant fluctuations with frequent peak periods, you can enable the I/O performance burst feature for premium performance disks. This allows your disk's IOPS to exceed the maximum IOPS limit during peak periods, providing higher I/O capabilities to meet your burst business requirements. This topic describes how to enable and disable the I/O performance burst feature for premium performance disks of RDS MySQL instances by using the console and API operations.
Prerequisites
The storage type of the RDS MySQL instance is premium performance disk.
Feature introduction
After the I/O performance burst feature is enabled for premium performance disks, the maximum IOPS and throughput limits of the instance increase. The following table describes the differences between instances with and without the I/O performance burst feature enabled:
When you enable the I/O performance burst feature for a primary instance, the feature is also enabled for the secondary instance. The feature is not automatically enabled for read-only instances. You need to enable it on the details page of each read-only instance.
Scenario | Maximum IOPS | Maximum throughput |
I/O performance burst disabled |
|
|
I/O burst enabled |
|
|
For information about
Enhanced IOPS valueandEnhanced I/O bandwidth value, see [Product/Feature Change] Baseline I/O performance improvement for RDS premium performance disks.If the throughput of an RDS instance reaches the upper limit, the IOPS of the RDS instance is affected. If the IOPS of an RDS instance reaches the upper limit, the throughput of the RDS instance is affected.
The preceding formulas do not apply to disk instances that use general-purpose instance types because general-purpose instance types share resources and cannot guarantee maximum IOPS and maximum I/O bandwidth.
For information about the maximum IOPS and maximum I/O bandwidth of instance types in the preceding formulas, see Primary ApsaraDB RDS for MySQL instance types of RDS Standard Edition (formerly X86) and Primary ApsaraDB RDS for MySQL instance types of RDS Yitian Edition (formerly ARM).
The following table describes how to calculate the IOPS that corresponds to the maximum I/O bandwidth mentioned in the preceding calculations.
RDS product
IOPS calculation method
Remarks
RDS MySQL
Maximum I/O bandwidth of instance type (Gbit/s)x1024x1024÷8÷16In this calculation, the value 8 indicates 8 bits, and 8 bits form a byte. The value 16 indicates that the amount of data involved in an I/O operation on an ApsaraDB RDS for MySQL instance is 16 KB.
Behavior
The process of enabling or disabling the I/O performance burst feature does not cause transient connections. In most cases, this process does not affect your business. In some cases, the IOPS of the RDS instance may fluctuate. We recommend that you perform this operation during off-peak hours.
Limit
Enabling or disabling the I/O performance burst feature takes several minutes. The specific time depends on the usage of the instance (read and write traffic).
Fees
A fee exemption campaign is in progress for the I/O performance burst feature of premium performance disks. Starting from June 20, 2024, no fees are charged for using the I/O performance burst feature. Discounts will still be available after the campaign ends. For more information, see [Campaign/Price Adjustment] Fee exemption campaign for the I/O performance burst feature of RDS premium performance disks.
Billing description
Billing unit price
Hourly I/O performance burst fee of an instance = (Total I/O performance burst volume of all nodes in the instance - Free quota) × Unit price
I/O performance burst unit price: USD 0.0015 per 10,000 I/O operations.
The I/O performance burst volume fees for premium performance disks of RDS instances (including primary and secondary nodes) are charged only on a pay-as-you-go basis. The fees are calculated and billed on an hourly basis in units of 10,000 I/O operations. If the number of I/O operations is less than 10,000, the system charges fees for 10,000 I/O operations.
Free I/O performance burst volume quota
The following table describes the free quotas for I/O performance burst volumes of premium performance disks for different RDS instance types:
Instance type | Free quota |
RDS Basic Edition | 300,000 per hour |
RDS High-availability Edition | 600,000 per hour |
RDS Cluster Edition | 800,000 per hour |
Instance I/O performance burst volume: Sum of I/O performance burst volumes of all nodes in the instance
RDS edition | Instance I/O performance burst volume |
RDS Basic Edition | I/O performance burst volume of the single node |
RDS High-availability Edition | I/O performance burst volume of the primary node + I/O performance burst volume of the secondary node |
RDS Cluster Edition | I/O performance burst volume of the primary node + I/O performance burst volumes of all secondary nodes |
If the I/O loads on the primary RDS instance are heavy and an I/O burst is triggered, an I/O burst is also triggered on the secondary RDS instance to ensure data and service consistency. The I/O performance burst volume of the secondary node is basically the same as that of the primary node.
The I/O performance burst feature for read-only instances must be enabled separately. The billing standard is the same as that for primary nodes. If a read-only instance is of RDS High-availability Edition, the fees include the I/O performance burst fees for both the primary and secondary nodes.
I/O performance burst volume of a single node: Part that exceeds 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 performance burst feature is disabled.
Example scenario | A user purchases an RDS High-availability Edition instance (with primary and secondary nodes) with a 200 GB premium performance disk. The baseline IOPS of the instance is 12,000. After the I/O performance burst feature is enabled: During the period from 00:00:00 to 01:00:00, I/O bursts occur from 00:00:00 to 00:00:27 and from 00:53:00 to 00:53:33, with IOPS consistently at 22,000. During the rest of the time, the IOPS does not exceed the baseline value, and no I/O bursts occur. |
Burst time | In the preceding example, burstable I/O operations are generated and the total burst time is 60 seconds. The value 60 is obtained by using the following calculation: 27 + 33 = 60. |
I/O performance burst volume of a single node in the hour | (22,000 - 12,000) × 1 × 60 = 600,000. |
Total I/O performance burst volume of the instance in the hour | 600,000 + 600,000 = 1,200,000. The numbers of burstable I/O operations on the primary and secondary RDS instances are each 600,000. |
Billing example
For example, if the I/O performance burst volume of an RDS High-availability Edition instance is 602,000 I/O operations per hour, the I/O performance burst fee is calculated as follows:
Actual I/O performance burst volume | 602,000 I/O operations per hour |
Free quota | 600,000 I/O operations per hour |
Excess over quota | 2,000 I/O operations |
Actual I/O performance burst fee | 10,000 × USD 0.0015 per 10,000 I/O operations = USD 0.0015 |
Enable or disable I/O performance burst
Visit the RDS instance list, select a region at the top, and click the ID of the target instance.
In the section, click Premium Performance Disk Switch Settings to the right of Premium Performance Disk, and enable or disable the I/O Performance Burst feature.
References
Related API operation
API | Description |
When you configure the I/O performance burst feature for premium performance disks:
|