Premium ESSD is a new storage class available for RDS SQL Server. It is compatible with all features of an enterprise SSD (ESSD), except for the pause instance feature. Premium ESSD includes the I/O performance burst feature, which provides higher input/output operations per second (IOPS) and queries per second (QPS) to accommodate fluctuating I/O demands during peak business hours. This topic describes the main features of Premium ESSDs and explains how to use them to improve database performance.
Core features of Premium ESSDs
I/O performance burst feature: During peak business hours, you can enable the I/O performance burst feature to allow the disk's IOPS to exceed its baseline, providing higher I/O capabilities. This feature is suitable for scenarios with frequent traffic spikes.
Data archiving to OSS feature: To reduce storage costs for large amounts of data, you can archive infrequently used databases to Alibaba Cloud Object Storage Service (OSS).
For more information about the performance of Premium ESSDs, see Performance data of different storage classes.
Use Premium ESSDs
RDS SQL Server supports using Premium ESSDs in the following ways.
Existing instances
If you have an instance that uses an ESSD, you can upgrade its storage class to Premium ESSD to improve I/O performance. This applies to any ESSD performance level (PL).
Prerequisites
The instance must use the ESSD storage class with a storage capacity of 40 GB or greater. Serverless instances are not supported.
Impacts
The change takes effect immediately without causing a transient disconnection and typically does not affect your services. However, a brief IOPS fluctuation may occur in rare cases. We recommend that you perform this operation during off-peak hours.
Notes
When you upgrade the storage class of an instance from ESSD to Premium ESSD, the change applies to all primary and secondary nodes (for Cluster Edition), primary and secondary instances (for High-availability Edition), and the primary instance (for Basic Edition). The change does not apply to the read-only instances associated with the primary instance. To change the storage class of a read-only instance, you must perform the operation on the details page of that specific read-only instance.
When you upgrade an ESSD to a Premium ESSD, you can only configure the I/O performance burst feature. You cannot modify other settings during this process.
After you upgrade an ESSD to a Premium ESSD, you cannot revert it to another storage class. Proceed with caution.
Billing
When you upgrade an ESSD to a Premium ESSD without enabling the I/O performance burst feature, the cost is the same as for a PL1 ESSD. However, if you enable the I/O performance burst feature during the upgrade, you are billed based on your I/O burst usage.
There is a price difference between enterprise SSDs (ESSDs) (PL2 and PL3) and premium performance disks. The exact difference is shown on the order generated in the console at the time of the change.
For a given period, a Premium ESSD is more cost-effective than a PL2 or PL3 ESSD if the instance experiences shorter durations of high I/O activity.
Procedure
Log on to the ApsaraDB RDS console and go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the instance ID.
In the Basic Information section, click Upgrade Storage Type next to Storage Type.
On the Change Specifications page, read the Terms of Service and click Confirm Order. Then, complete the payment.
After the payment is complete, the instance status changes to Upgrading. The upgrade is complete when the instance status changes to Running.
New instances
When you purchase a new instance, you can directly select the Premium ESSD storage class on the purchase page.
You cannot purchase Premium ESSDs if you select the Serverless billing method.
Enable or disable I/O performance burst
You can enable or disable the I/O performance burst feature in the console (I/O Performance Burst) or by calling the API (ModifyDBInstanceSpec - Change RDS instance specifications). When you use the API to configure the I/O performance burst feature for a Premium ESSD, ensure that:
The DBInstanceStorageType parameter is set to general_essd (Premium ESSD).
Set
BurstingEnabled=trueto enable I/O performance burst, or set it tofalseto disable it.Other parameters, such as instance type and storage capacity, must remain unchanged.
Use data archiving to OSS
You can configure a data archiving policy in the console (Data Archiving to OSS).
References
For more information about other storage classes that RDS SQL Server supports, see Introduction to storage classes.