Automatic Storage Scale-up and Storage Overuse
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Insufficient database storage space may prevent data writes and can even cause database service interruptions due to full disks, severely impacting normal business operations. TDSQL-C for MySQL supports the Automatic storage scale-up feature (referred to as automatic scale-up) and the storage overuse feature to effectively avoid service interruptions caused by insufficient storage. After you enable the automatic storage scale-up feature, the system automatically scales out storage using a yearly/monthly subscription model when storage utilization reaches a preset threshold. After you enable the storage overuse feature, you can continue writing data when storage utilization reaches 100%. The excess part will be charged in pay-as-you-go mode. You can choose either feature as a solution to prevent storage shortages. This document describes the automatic storage scale-up and storage overuse features and provides related operational guidance.
Note:
The automatic scale-up and storage overuse features are mutually exclusive. You can enable only one of them at a time. To switch between features, first disable the currently enabled feature. If you do not disable the currently enabled feature, the system automatically disables the previous feature by default after you enable another feature.
Feature Strengths
As business data continues to grow, database storage space may become insufficient. Enabling automatic storage scale-up or storage overuse offers the following advantages:
Eliminates manual Ops: The system automatically performs scale-up based on preset policies, eliminating the need for continuous monitoring of storage utilization.
Ensures business continuity: It triggers scale-up in advance when storage is about to be exhausted, preventing instances from becoming read-only or experiencing write failures due to full disks.
Enables flexible cost control: The automatic storage scale-up feature allows you to customize the trigger threshold, scale-up step, and scale-up upper limit, balancing cost and availability according to business needs.
Supported instance types
TDSQL-C for MySQL clusters with an instance mode of pre-configured resources and a storage billing mode of yearly/monthly subscription support the automatic scale-up and storage overusefeatures.
Prerequisites
You have created a cluster. For details, see Creating a Cluster.
The cluster status is Running.
Your Tencent Cloud account has sufficient balance.
Fee Instructions
After you enable the automatic storage scale-up feature, the incurred fees are settled according to the yearly/monthly subscription billing mode:
Category | Description |
Scale-out Storage Space Fee | Calculate the price difference for the remaining period based on the total storage capacity of the scaled-out cluster. |
Expiration Time Alignment | The expiration time of the scaled-out storage space is aligned with that of the original cluster. |
Billing Example:
Suppose you purchased a TDSQL-C for MySQL cluster with a yearly/monthly subscription on June 1, 2026, with a storage capacity of 1000 GB and a purchase period of one year. After you enable automatic storage scale-up, the cluster is automatically scaled out by 200 GB on December 1, 2026, because the storage utilization reaches the threshold. The total storage capacity after the scale-up is 1200 GB:
The fee = the scale-up step × the storage unit price × the remaining period ratio.
The remaining period ratio = the remaining days / the total purchase days (183/365 ≈ 0.50 in this example).
Note:
For the storage unit price, you can refer to the yearly/monthly subscription price under primary storage in Product Pricing.
When you choose to use the storage overuse feature instead of the automatic scale-up feature, the storage fees for the overuse portion are settled according to the pay-as-you-go billing mode:
Category | Description |
Storage fee for overused portion | Charged based on the pay-as-you-go billing mode. |
Billing Granularity | Settled hourly, with precision down to the GB level. |
Prepayment Required or Not | No prepayment is required for the excess portion, and fees are charged based on actual usage. |
Note:
For the storage unit price, you can refer to the pay-as-you-go price under primary storage in Product Pricing.
Operation Steps
Enabling Automatic Scale-up
1. Log in to the TDSQL-C for MySQL console.
2. Click the target cluster in the cluster list on the left to go to the cluster management page.
3. After navigating to Instance Info > Primary Storage, turn on the automatic scale-up button.
4. In the pop-up window, complete the following configurations, and click OK.
Parameter | Description |
Automatic Storage Scale-Up Status | Automatic scale-up feature switch. Optional values: Enable, Disable. Default value: Disable. |
Automatic Scale-Up Trigger Threshold | Automatic scale-up is triggered when storage utilization reaches this value. Optional values: 70%, 80%, -90%, 95%. Default value: 70%. |
Automatic Storage Scale-Up Upper Limit | Maximum storage capacity limit for automatic scale-up. Since the maximum storage capacity may vary by specification, the automatic scale-up range for different clusters is: [Current cluster storage capacity + Scale-out step, Maximum storage capacity corresponding to the current cluster specification]. For the maximum storage capacity corresponding to different specifications, see Product Specifications. Default value: Current cluster storage capacity + Scale-out step. |
Scale-Up Increment | Storage capacity increment per automatic scale-up. Range: 20 GB - 1000 GB. Default value: 20 GB. |
Note:
If the storage overuse feature is enabled, you must also select the configuration item "Storage overuse is currently enabled for this cluster. Enabling automatic scale-up will automatically disable storage overuse." Then, click OK.
After the feature is enabled, if you need to modify the automatic scale-up configuration, you can also click the automatic scale-up button to go to the configuration page and make modifications (threshold, upper limit, step size).
Disabling Automatic Scale-up
Note:
Disabling the automatic scale-up operation only disables the automatic scale-up feature. The storage capacity that has been scaled out will not be automatically reduced.
1. Log in to the TDSQL-C for MySQL console.
2. Click the target cluster in the cluster list on the left to go to the cluster management page.
3. After navigating to Instance Info > Primary Storage, disable the automatic scale-up button.
4. In the pop-up window, select Disable and click OK.
Enabling Storage Overuse
Note:
If the automatic scale-up feature is enabled, it will be automatically disabled during the process of enabling storage overuse.
1. Log in to the TDSQL-C for MySQL console.
2. Click the target cluster in the cluster list on the left to go to the cluster management page.
3. After navigation to Instance Info > Primary Storage is performed, turn on the storage overuse button.
4. In the pop-up window, select "When storage overuse is enabled, the overused storage traffic will be billed on a pay-as-you-go basis." and click OK. If the automatic scale-up feature is enabled, in the pop-up window, select "When storage overuse is enabled, automatic scale-up will be automatically disabled." and then click OK.
Disabling Storage Overuse
1. Log in to the TDSQL-C for MySQL console.
2. Click the target cluster in the cluster list on the left to go to the cluster management page.
3. After you navigate to Instance Info > Primary Storage, disable the storage overuse button.
4. In the pop-up window, select "Are you sure you want to disable storage overuse?" and click OK.
FAQs
Q1: What Is the Difference Between Automatic Scale-Up and Storage Overuse?
For a comparison between the automatic scale-up and storage overuse features, see the following table:
Comparison Item | Automatic scale-up | Storage overuse |
Trigger Condition | Storage utilization reaches the preset threshold (70% - 95%). | Storage utilization reaches 100%. |
Billing Mode | Yearly/monthly subscription | Pay-as-you-go |
Service guarantee | Scale out in advance to avoid service interruption. | Write operations are still allowed after overuse, but at a higher cost. |
Mutual Exclusion | Mutually exclusive with storage overuse | Mutually exclusive with automatic scale-up |
Q2: Does Automatic Scale-Out Affect Services?
No. The automatic scale-up process has the following characteristics:
Database services remain uninterrupted during execution.
Read and write requests are processed normally without perceptible latency.
The backup feature remains unaffected.
After the scale-up is complete, the expiration time is automatically aligned with that of the original cluster.
Q3: What to Do After the Scale-Out Limit Is Reached?
When the storage capacity reaches the configured scale-up upper limit, the system will stop the automatic scale-up. You can take the following measures:
1. Increase the scale-up upper limit: Modify the automatic scale-up configuration to raise the storage automatic scale-up upper limit.
2. Clean up data: Clean up unnecessary historical data or temporary files to reduce storage utilization.
3. Upgrade the specification: If the maximum storage capacity corresponding to the current cluster specification has been reached, consider upgrading to a higher specification.
4. Switch to storage overuse: Disable automatic scale-up and then enable the storage overuse feature as a temporary contingency measure.
Q4: Can I Modify or Disable Automatic Scale-Out Configuration at Any Time?
Yes. You can modify the automatic scale-up parameters (trigger threshold, step size, upper limit) or completely disable this feature in the console at any time.
Modify the configuration: The new configuration will take effect upon the next trigger.
Disable the feature: After it is disabled, automatic scale-up will no longer occur. If you need to scale out, perform the operation manually or re-enable the feature.
Note: If the cluster is performing an automatic scale-up task, you must wait until the task is complete before you can modify the configuration.
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