If your business workloads fluctuate significantly and experience frequent peaks, you can enable the I/O burst feature for your ESSD AutoPL disks. This allows the disk's input/output operations per second (IOPS) to exceed the provisioned limit, providing higher I/O capabilities during peak times to meet sudden business demands. This topic describes how to enable and disable the I/O burst feature for the ESSD AutoPL disks of a PolarDB for MySQL cluster in the console.
Scope
The PolarDB for MySQL cluster uses ESSD AutoPL disks for storage.
The I/O burst feature is not supported for serverless clusters.
Overview
After you enable I/O burst, the maximum IOPS and throughput of the cluster increase. The following table compares the cluster before and after I/O burst is enabled.
If you enable I/O burst on the primary node, it is also enabled on the secondary nodes.
Scenario | Maximum IOPS | Maximum throughput |
I/O burst disabled |
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I/O burst enabled |
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Throughput and IOPS are interdependent. When one reaches its limit, the other is also affected.
For more information about the maximum IOPS and maximum I/O bandwidth in the formulas, see Compute node specifications for x86 architecture and Compute node specifications for YiTian ARM architecture.
The IOPS corresponding to the maximum I/O bandwidth is calculated as follows:
PolarDB engine version: PolarDB for MySQL Standard Edition.
IOPS formula: Maximum I/O bandwidth of the cluster specification (Gbit/s) × 1024 × 1024 ÷ 8 ÷ 16
Note: The number 8 is used because 1 byte equals 8 bits. The number 16 is used because the data volume of a single I/O operation in PolarDB for MySQL is 16 KB.
Impacts
Enabling or disabling I/O burst does not cause transient disconnections and generally does not affect your services. In rare cases, the cluster IOPS may fluctuate. Perform this operation during off-peak hours.
Notes
Enabling or disabling I/O burst takes several minutes. The exact duration depends on the cluster's usage, such as read and write traffic.
Billing
The fees for an ESSD AutoPL disk include the following: disk capacity fees, provisioned performance fees, and performance burst fees.
Disk capacity fees: These fees are charged when the disk is created. After purchase, the disk provides the same baseline performance as a PL1 ESSD. For more information about billing rules, see Billing rules for storage space.
Provisioned performance fees: Charged on a pay-as-you-go basis after the feature is enabled.
Performance burst fees: Charged on a pay-as-you-go basis after the feature is enabled.
Disk billing method | Disk fees (USD) | Cloud Disk Performance |
Subscription
Duration: 1 month |
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Pay-as-you-go
Billing duration: 24 hours |
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The billable usage for an ESSD AutoPL disk includes basic storage space and provisioned IOPS.
The I/O burst fees for a PolarDB cluster, including its primary and secondary nodes, are charged on a pay-as-you-go basis. Bills are generated hourly. Fees are calculated per 10,000 I/O operations. If the number of I/O operations is less than 10,000, it is rounded up to 10,000.
Procedure
Enable I/O burst when you create a new cluster
Go to the PolarDB cluster purchase page.
During cluster configuration, set Storage Type to ESSD AutoPL and turn on the I/O burst switch.
Enable or disable I/O burst for an existing cluster
Log on to the PolarDB console. In the upper-left corner, select the region where your cluster is deployed. Click the ID of the cluster.
In the Basic Information section, find the Distributed Storage section and click Change Storage Configuration.
On the Upgrade/Downgrade page, enter a value for Provisioned IOPS for AutoPL Disk as needed. For Enable I/O Burst, select Disable or Enable.
Set Switch Time to Switch Now or Scheduled Switch.
If you select Scheduled Switch, you can specify a time within the next 24 hours. The configuration upgrade task will be completed within 30 minutes after the selected time.
You can also view the task details or cancel the task on the Scheduled Tasks page. For more information, see Scheduled tasks.
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