Premium ESSD is a storage type for ApsaraDB RDS that is compatible with all features of ESSDs and delivers higher baseline I/O performance than PL1 ESSDs, with three optional features: Buffer Pool Extension (BPE), I/O burst, and data archiving. Use it when your workload demands higher baseline throughput than PL1 ESSDs provide, or when you need elastic I/O scaling, buffer pool acceleration, or cost-effective cold data storage.
When to use Premium ESSD
| Situation | Recommended feature |
|---|---|
| Read I/O is heavy and temporary tables are frequent | Buffer Pool Extension (BPE) |
| I/O loads spike with business peaks | I/O burst |
| Tables are large but rarely accessed or modified | Data archiving |
Premium ESSDs are supported by all RDS instance types (cloud disk version).
Serverless RDS MySQL instances currently support only the I/O burst feature of Premium ESSDs.
Features
Buffer Pool Extension (BPE)
BPE expands the buffer pool of your RDS instance, which accelerates caching, reduces SQL execution time, and reduces I/O jitter. The result is improved read/write performance and greater instance stability — without upgrading instance specifications or modifying application code.
For details, see Use the I/O acceleration feature of general ESSDs.
I/O burst
I/O burst removes the IOPS ceiling during peak hours. When I/O loads spike, the system automatically raises the I/O limit. When loads drop, it restores the limit automatically — delivering elastic I/O scaling without wasted capacity.
The problem I/O burst solves
Business peaks, large transactions, full table scans, and queries returning large result sets can all push I/O usage to 100%, even when CPU, memory, and disk space are sufficient. Three common responses — and their tradeoffs:
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Do nothing: I/O hits the ceiling, queries time out, and connection errors occur.
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Upgrade instance specifications: I/O capacity improves, but CPU and memory sit idle and cost more.
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Upgrade storage type (for example, from PL1 ESSD to PL2 ESSD): addresses the immediate spike, but wastes storage resources and increases cost once loads normalize.
I/O burst handles the spike automatically and scales back down when it passes.
For details, see I/O burst feature.
Data archiving
Data archiving moves infrequently accessed data to an OSS bucket, reducing storage costs by 80% compared to PL1 ESSDs. Access performance for archived data is lower than for active data.
For details, see Data archiving feature.
The Buffer Pool Extension (BPE) feature is free for RDS MySQL general-purpose instance types.
Baseline I/O performance
Premium ESSDs provide higher baseline IOPS and I/O bandwidth than PL1 ESSDs for instances with at least 100 GB of storage.
| Storage capacity | Baseline before increase (same as PL1 ESSD) | Baseline after increase | Increment |
|---|---|---|---|
| 100 GB – 999 GB | Bandwidth: 125–350 MB/s; IOPS: 6,800–50,000 | Bandwidth: 225–450 MB/s; IOPS: 13,200–56,400 | Bandwidth: +100 MB/s; IOPS: +6,400 |
| 1,000 GB – 1,999 GB | Bandwidth: 350 MB/s; IOPS: 50,000 | Bandwidth: 500 MB/s; IOPS: 59,600 | Bandwidth: +150 MB/s; IOPS: +9,600 |
| 2,000 GB – 3,999 GB | Bandwidth: 350 MB/s; IOPS: 50,000 | Bandwidth: 550 MB/s; IOPS: 62,800 | Bandwidth: +200 MB/s; IOPS: +12,800 |
| 4,000 GB – 15,999 GB | Bandwidth: 350 MB/s; IOPS: 50,000 | Bandwidth: 600 MB/s; IOPS: 66,000 | Bandwidth: +250 MB/s; IOPS: +16,000 |
| 16,000 GB – 63,999 GB | Bandwidth: 350 MB/s; IOPS: 50,000 | Bandwidth: 700 MB/s; IOPS: 72,400 | Bandwidth: +350 MB/s; IOPS: +22,400 |
For details, see [Product changes] The baseline I/O performance of Premium ESSDs for ApsaraDB RDS instances is increased.
After the baseline I/O performance improvement takes effect, the I/O burst feature uses the improved baseline as its starting point.
I/O burst performance
Enabling I/O burst raises the maximum IOPS and throughput of an instance beyond the standard limits.
| Scenario | Maximum IOPS | Maximum throughput |
|---|---|---|
| I/O burst disabled | min{50000 + IOPS increment, Maximum IOPS for instance type, IOPS for max I/O bandwidth, 1800 + 50 × Storage capacity + IOPS increment} |
min{350 + I/O bandwidth increment, Maximum I/O bandwidth for instance type, 120 + 0.5 × Storage capacity + I/O bandwidth increment} MB/s |
| I/O burst enabled | min{1000000, Maximum IOPS for instance type, IOPS for max I/O bandwidth} |
min{4000, Maximum I/O bandwidth for instance type} MB/s |
IOPS calculation for RDS MySQL
To calculate the IOPS that corresponds to the maximum I/O bandwidth for an instance type:
IOPS = Maximum I/O bandwidth (Gbit/s) × 1024 × 1024 / 8 / 16In this formula, 8 converts bits to bytes, and 16 reflects the 16 KB I/O operation size for ApsaraDB RDS for MySQL instances.
ForIOPS incrementandI/O bandwidth incrementvalues, see Baseline I/O performance improvement of Premium ESSDs for RDS.
If throughput reaches its upper limit, IOPS is also affected, and vice versa.
These formulas do not apply to general-purpose instance types with cloud disks, as they share resources and cannot guarantee maximum IOPS or maximum I/O bandwidth.
For maximum IOPS and I/O bandwidth by instance type, 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).
Enablement behavior
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Enabling I/O burst on a primary instance automatically enables it on the secondary instance.
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For read-only instances, enable the feature separately on each instance's details page.
Limitations
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Storage capacity ranges from 10 GB to 64,000 GB.
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Changing the storage type from Premium ESSD to any other storage type is not supported. Changing from ESSD to Premium ESSD is supported. For details, see Change the storage type from ESSD to Premium ESSD.
Billing
The total cost of a Premium ESSD instance consists of:
Premium ESSD fee = Storage space fee + I/O burst fee + BPE fee + Data archiving OSS feeBPE is free for RDS MySQL general-purpose instance types.
Storage space fee
Both subscription and pay-as-you-go billing methods are supported. Billing rules follow the same structure as PL1 ESSDs. For a full breakdown, see Billable items.
Regions where Premium ESSD is cheaper than PL1 ESSD
In the following regions, the unit price of a Premium ESSD is lower than that of a PL1 ESSD:
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).
The savings vary by billing method:
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Pay-as-you-go: up to 60% more cost-effective than PL1 ESSDs
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Subscription: up to 43% more cost-effective than PL1 ESSDs
Regions where Premium ESSD has the same price as PL1 ESSD
In the following regions, the unit price of a Premium ESSD equals the unit price of a PL1 ESSD:
China (Hangzhou), China (Shanghai), China (Beijing), China (Shenzhen), China (Nantong), China (Qingdao), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Heyuan), China (Guangzhou), and China (Chengdu).
When an RDS instance handles many I/O operations in a shorter burst within a specific time window, Premium ESSDs are more cost-effective than PL2 and PL3 ESSDs — you pay for base storage rather than a permanently upgraded tier.
For per-feature billing details, see:
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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 rules are the same as those of a PL1 ESSD. For more information, see Billable items.
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In the following regions, Premium ESSDs are more cost-effective than PL1 ESSDs regardless of the billing method, and the unit price of a Premium ESSD is lower than the unit price of a PL1 ESSD:
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 Premium ESSD and a PL1 ESSD varies based on the billing method:
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Pay-as-you-go: Premium ESSDs can be up to 60% more cost-effective than PL1 ESSDs.
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Subscription: Premium ESSDs can be up to 43% more cost-effective than PL1 ESSDs.
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In the following regions, the unit price of a Premium ESSD is the same as the unit price of a PL1 ESSD:
China (Hangzhou), China (Shanghai), China (Beijing), China (Shenzhen), China (Nantong), China (Qingdao), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Heyuan), China (Guangzhou), and China (Chengdu)