This topic describes the concept, performance, performance limits, scenarios, billing, and related operations of Premium ESSDs to help you decide whether to use Premium ESSDs.
Introduction to feature
Alibaba Cloud Premium ESSD is a new storage type supported by ApsaraDB RDS. It is compatible with all features, provides better baseline I/O performance than PL1 ESSDs, and supports I/O burst, Buffer Pool Extension (BPE), and data archiving to OSS.
Buffer Pool Extension (BPE)
After you enable the Buffer Pool Extension (BPE) feature, you can expand the cache pool size of your instance, implement cache acceleration, and improve the overall read and write performance of your RDS instance. This feature significantly reduces the impact of I/O jitter on database operations and improves stability. The feature is suitable if you want to improve the I/O performance of the RDS instance without upgrading instance specifications or modifying business code. For more information, see Buffer Pool Extension (BPE) feature.
I/O burst
After you enable the I/O burst feature, the IOPS of the disk is not limited to the maximum IOPS, which allows you to obtain higher I/O capabilities during peak business periods and meet burst business requirements. The feature is suitable for scenarios in which I/O loads are heavy and fluctuating. For more information, see I/O burst feature.
Data archiving
After you enable the data archiving feature, you can archive infrequently accessed data to OSS buckets. Compared to ESSDs of performance level 1 (PL1), general ESSDs help reduce the storage cost by 80%. The feature is suitable if your RDS instance contains infrequently accessed or modified tables. For more information, see Data archiving feature.
Supported product series
All RDS instance types (disk-based) support Premium ESSDs.
Serverless ApsaraDB RDS for MySQL instances currently support only the I/O burst feature of Premium ESSDs.
Performance of Premium ESSDs
Baseline I/O performance
Premium ESSDs provide improved baseline I/O performance. The following table shows the differences in baseline performance improvements for Premium ESSDs with different storage capacities. For more information, see [Product/Feature Change] Baseline I/O performance improvement for RDS Premium ESSDs.
This performance improvement requires that the storage capacity of Premium ESSDs is not less than 100 GB.
After this performance improvement, when you use the I/O burst feature, the burst is performed based on the improved baseline I/O performance.
Storage capacity of Premium ESSDs | Baseline before the increase (the same as that of PL1 ESSDs) | Baseline after the increase | Increment |
100 GB ≤ Storage capacity < 1,000 GB | I/O bandwidth: 125 MB/s to 350 MB/s IOPS: 6,800 to 50,000 | I/O bandwidth: 225 MB/s to 450 MB/s IOPS: 13,200 to 56,400 | I/O bandwidth: 100 MB/s IOPS: 6,400 |
1,000 GB ≤ Storage capacity < 2,000 GB | I/O bandwidth: 350 MB/s IOPS: 50,000 | I/O bandwidth: 500 MB/s IOPS: 59,600 | I/O bandwidth: 150 MB/s IOPS: 9,600 |
2,000 GB ≤ Storage capacity < 4,000 GB | I/O bandwidth: 350 MB/s IOPS: 50,000 | I/O bandwidth: 550 MB/s IOPS: 62,800 | I/O bandwidth: 200 MB/s IOPS: 12,800 |
4,000 GB ≤ Storage capacity < 16,000 GB | I/O bandwidth: 350 MB/s IOPS: 50,000 | I/O bandwidth: 600 MB/s IOPS: 66,000 | I/O bandwidth: 250 MB/s IOPS: 16,000 |
16,000 GB ≤ Storage capacity < 64,000 GB | I/O bandwidth: 350 MB/s IOPS: 50,000 | I/O bandwidth: 700 MB/s IOPS: 72,400 | I/O bandwidth: 350 MB/s IOPS: 22,400 |
Performance of Premium ESSD features
Buffer Pool Extension (BPE)
After you enable Buffer Pool Extension (BPE), you can effectively improve read and write performance, reduce SQL execution time, and reduce the impact of I/O jitter on database operations, thereby improving stability. For more information, see Buffer Pool Extension (BPE) feature.
I/O burst
After you enable I/O burst for a Premium ESSD, the maximum IOPS and throughput of the instance are increased. The following table shows the differences between instances with and without I/O burst enabled:
After you enable the I/O burst feature for a primary node, the feature is automatically enabled for the secondary node. The feature is not automatically enabled for read-only instances. You must enable the feature on the details page of each read-only instance.
Scenario | Maximum IOPS | Maximum throughput |
I/O burst not enabled |
|
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I/O burst enabled |
|
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For information about
Increased IOPS valueandIncreased I/O bandwidth value, see Baseline I/O performance improvement for RDS Premium ESSDs.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 formulas do not apply to disk-based 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 Standard Edition (formerly X86) instance types and Primary ApsaraDB RDS for MySQL Enterprise Edition (formerly ARM) instance types.
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 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.
Data archiving
After you enable the data archiving feature for Premium ESSDs and archive infrequently accessed data, you can reduce storage costs. However, the performance of accessing archived data is relatively low.
Scenarios
Buffer Pool Extension (BPE)
Buffer Pool Extension (BPE) is suitable for scenarios with high read I/O loads and frequent use of temporary tables.
I/O burst
Premium ESSDs are suitable for handling high and fluctuating I/O loads.
Business peaks, large transactions, full table scans, and queries that return large amounts of data can all cause I/O loads to increase. Sometimes CPU, memory, and storage space are relatively sufficient, but the I/O usage rate is close to or reaches 100%. In these scenarios, you must upgrade the instance specifications or storage type of your RDS instance. For example, you can upgrade the storage type from ESSD PL1 to ESSD PL2.
If you do not upgrade the instance specifications or storage type, the I/O loads reach the upper limit. As a result, the instance performance decreases, queries time out, and connection errors occur.
If you upgrade instance specifications, the I/O performance can meet your business requirements, but the CPU, memory, and storage resources are idle and wasted.
If you upgrade the storage type, the I/O usage is increased within a short period of time, but storage resources are wasted and costs are increased when the I/O loads decrease.
The I/O burst feature of Premium ESSDs can solve these problems. After you enable the I/O burst feature, when I/O loads are high, I/O burst is automatically triggered to increase the I/O upper limit. When I/O loads decrease, the I/O upper limit is automatically restored. This implements serverless I/O performance and prevents I/O performance and cost waste.
Data archiving
Data archiving is suitable if your RDS instance contains infrequently accessed or modified tables.
Limits
The storage capacity of Premium ESSDs ranges from 10 GB to 64,000 GB.
Premium ESSDs cannot be changed to any other storage type, but ESSDs can be changed to Premium ESSDs. For more information, see Change ESSDs to Premium ESSDs.
Billing
Billing method
Premium ESSD fee = RDS storage space fee + I/O burst fee + Buffer Pool Extension (BPE) fee + Data archiving to OSS fee.
For detailed billing information about each featuresee:
The Buffer Pool Extension (BPE) feature is free for RDS MySQL general-purpose instance types.
RDS storage space fee
The fees for ESSDs (PL2 and PL3) and Premium ESSDs are different. The difference is based on the order displayed in the console when you make the change.
Within a specific time period, the shorter the duration of high I/O, the more cost-effective Premium ESSDs are compared to PL2 and PL3 ESSDs.
Premium ESSD fee = Storage space fee + I/O burst fee + Buffer Pool Extension (BPE) fee + Data archiving to OSS fee.
You are charged for the storage capacity that you purchase for your RDS instance. The subscription and pay-as-you-go billing methods are supported. The billing method is the same as that of PL1 ESSDs. For more information, see Billable items.
In the following regions, Premium ESSDs are more cost-effective than PL1 ESSDs under different billing methods, and the unit price of storage space itself is lower than that of PL1 ESSDs.
China (Hong Kong), Singapore, Malaysia (Kuala Lumpur), Indonesia (Jakarta), Philippines (Manila), Thailand (Bangkok), Japan (Tokyo), South Korea (Seoul), US (Silicon Valley), US (Virginia), Germany (Frankfurt), UK (London), and UAE (Dubai).
NoteThe price difference between a general ESSD and a PL1 ESSD varies based on the billing method.
Pay-as-you-go: The unit price of Premium ESSDs is up to 60% lower than that of PL1 ESSDs.
Subscription: The unit price of Premium ESSDs is up to 43% lower than that of PL1 ESSDs.
In the following regions, the unit price of storage space for Premium ESSDs is the same as that for PL1 ESSDs.
China (Hangzhou), China (Shanghai), China (Beijing), China (Shenzhen), China (Nantong), China (Qingdao), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Heyuan), China (Guangzhou), China (Chengdu)