If your workloads significantly fluctuate and the peak hours frequently change, you can enable the I/O burst feature of general Enterprise SSDs (ESSDs) for an ApsaraDB RDS for MySQL instance. This way, the IOPS of general ESSDs is no longer limited by the maximum IOPS. This improves the I/O performance of the RDS instance to handle workload bursts during peak hours. This topic describes how to enable and disable the I/O burst feature of general ESSD for your RDS instance in the ApsaraDB RDS console and by calling API operations.
Prerequisites
The RDS instance uses the general ESSD storage type.
Feature description
If you enable the I/O burst feature of general ESSDs for an RDS instance, the maximum IOPS and maximum throughput of the RDS instance are increased. The following table compares the maximum IOPS and maximum throughput of an RDS instance before and after the I/O burst feature is enabled for the RDS instance.
If you enable the I/O burst feature for the primary RDS instance, the I/O burst feature is automatically enabled for the secondary RDS instance. If you want to enable the I/O burst feature for the read-only RDS instances of the primary RDS instance, you must go to the instance details page.
Scenario | Maximum IOPS | Maximum throughput |
I/O burst disabled |
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I/O burst enabled |
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For more information about
IOPS incrementandI/O bandwidth increment, see [Product changes/Feature changes] The baseline I/O performance of the general ESSDs of ApsaraDB RDS instances is increased.If the throughput of an RDS instance reaches the upper limit, the IOPS of the instance is affected. If the IOPS of an RDS instance reaches the upper limit, the throughput of the instance is affected.
The preceding calculations do not apply to RDS instances that use cloud disks and general-purpose instance types because these types of RDS instances share resources. As a result, the maximum IOPS and maximum I/O bandwidth cannot be guaranteed. For more information, see Instance types for primary ApsaraDB RDS for PostgreSQL instances.
For more information about the maximum IOPS and maximum I/O bandwidth of specific instance types, see Instance types for standard primary ApsaraDB RDS for MySQL instances (original x86 architecture) and Instance types for YiTian primary ApsaraDB RDS for MySQL instances (original ARM architecture).
The following table describes how to calculate the IOPS that corresponds to the maximum I/O bandwidth mentioned in the preceding calculations.
Service
IOPS calculation
Remarks
ApsaraDB RDS for MySQL
IOPS = Maximum I/O bandwidth for the instance type (Gbit/s) × 1024 × 1024/8/16
In 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.
Impacts
Enabling or disabling the I/O burst feature does not cause transient connections. In most cases, your workloads are not adversely affected. In some cases, the IOPS of the RDS instance may fluctuate. We recommend that you perform this operation during off-peak hours.
Usage notes
The time required to enable or disable the I/O burst feature varies based on the read and write traffic of the RDS instance. In most cases, several minutes are required to enable or disable the feature.
Billing rules
From June 20, 2024 to September 23, 2024, you can use the I/O burst feature free of charge. After the public preview ends, you are charged for the feature. The following section describes the billing rules of the feature.
Billing rules
Unit prices
Hourly fee for burstable I/O operations = (Total number of burstable I/O operations on all RDS instances in a database system - Free quota on burstable I/O operations) × Unit price of burstable I/O operations
Unit price of burstable I/O operations: USD 0.0015 per 10,000 burstable I/O operations
Only the pay-as-you-go billing method is supported. You are charged for the burstable I/O operations on general ESSDs of your RDS instances, including primary and secondary RDS instances. The system generates bills on an hourly basis. Fees are calculated per 10,000 I/O operations. For billing purposes, burstable I/O operations are rounded up to the next 10,000 I/O operations.
Free quota on burstable I/O operations
The free quota on burstable I/O operations varies based on the RDS edition. The following table describes the free quotas.
RDS edition | Free quota |
RDS Basic Edition | 300,000 per hour |
RDS High-availability Edition | 600,000 per hour |
RDS Cluster Edition | 800,000 per hour |
Number of burstable I/O operations: total number of burstable I/O operations on all RDS instances in a database system
RDS edition | Number of burstable I/O operations |
RDS Basic Edition | Number of burstable I/O operations on the RDS instance |
RDS High-availability Edition | Number of burstable I/O operations on the primary RDS instance + Number of burstable I/O operations on the secondary RDS instance |
RDS Cluster Edition | Number of burstable I/O operations on the primary RDS instance + Number of burstable I/O operations on all secondary RDS instances |
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 instances to ensure data and service consistency. The number of burstable I/O operations on the secondary RDS instance is the same as that on the primary RDS instance.
You must separately enable the I/O burst feature for a read-only RDS instance. The billing rules of the I/O burst feature for a read-only RDS instance are the same as those for the primary RDS instance. If the read-only RDS instance runs RDS High-availability Edition, the fee for the I/O burst feature includes the I/O burst fees that are generated for the primary and secondary RDS instances of the read-only RDS instance.
Number of burstable I/O operations on an RDS instance: Part that exceeds the baseline IOPS or throughput × Duration
The baseline I/O performance includes the baseline IOPS and baseline throughput and refers to the initial I/O performance of a general ESSD. The initial I/O performance is the maximum IOPS and the maximum throughput when the I/O burst feature is disabled.
Scenario | An RDS instance that runs RDS High-availability Edition and uses general ESSDs with 200 GB of storage capacity is created. The RDS instance has a secondary RDS instance. The baseline IOPS of the RDS instance is 12,000. The I/O burst feature is enabled for the RDS instance. From 00:00:00 to 01:00:00, burstable I/O operations are generated from 00:00:00 to 00:00:27 and from 00:53:00 to 00:53:33, and the IOPS during these periods of time remains 22,000. During other periods of time within the hour, the IOPS does not exceed the baseline and no burstable I/O operations are generated. |
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. |
Number of burstable I/O operations on an RDS instance within the hour | (22,000 - 12,000) × 1 × 60 = 600,000. |
Total number of burstable I/O operations on all RDS instances in the database system within 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 examples
For example, the number of burstable I/O operations on an RDS instance that runs RDS High-availability Edition is 602,000 within an hour. The following table describes the fee for burstable I/O operations.
Actual number of burstable I/O operations | 602,000 per hour |
Free quota | 600,000 per hour |
Excess burstable I/O operations | 2,000 I/O |
Fee for the actual number of burstable I/O operations | 10,000 × USD 0.0015 per 10,000 I/O operations = USD 0.0015 |
Procedure
Enable the I/O burst feature when you create an RDS instance
Set the Storage Type parameter to General ESSD and turn on I/O Burst.
Enable or disable the I/O burst feature for an existing RDS instance
Log on to the ApsaraDB RDS console and go to the Instances page. In the top navigation bar, select the region in which your RDS instance resides. Then, find the RDS instance and click the ID of the RDS instance.
In the Basic Information section of the page that appears, enable or disable the I/O burst feature.
References
Related operations
Operation | Description |
When you configure the I/O burst feature of a general ESSD, take note of the following items:
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