Alibaba Cloud provides ESSD AutoPL disks based on Enterprise SSDs (ESSDs). ESSD AutoPL disks inherit the features and performance of ESSDs and decouple disk capacity from disk performance. When you configure the capacity of ESSD AutoPL disks, you can configure provisioned performance and burst performance settings for the disks based on your business requirements. This topic describes the features, specifications, billing methods, and use scenarios of ESSD AutoPL disks and provides examples on how to configure the disks.
The instance to which an ESSD AutoPL disk is attached exerts pressure on the ESSD AutoPL disk. The performance of all applications that run on the instance, such as Alibaba Cloud Security, CloudMonitor, and Cloud Assistant, is included in the performance statistics of the ESSD AutoPL disk.
For information about common performance metrics of disks, see the Performance metrics section of the "Block storage performance" topic.
For information about ESSDs, see ESSDs.
Features
The total performance of an ESSD AutoPL disk is the sum of the baseline performance, provisioned performance, and burst performance.
Baseline performance
The baseline performance and pricing of an ESSD AutoPL disk is equivalent to the performance and pricing of an ESSD at performance level 1 (PL1 ESSD) that has the same specifications.
Provisioned performance
The performance provision feature allows you to configure provisioned performance settings for ESSD AutoPL disks to meet storage requirements that exceed the baseline performance without the need to extend the disks. This decouples disk capacity from disk performance.
Burst performance
By default, the performance burst feature is enabled for ESSD AutoPL disks. The feature allows ESSD AutoPL disks to burst their performance when spikes in read/write workloads occur and reduce the performance to the baseline level at times of normal workload. An ESSD AutoPL disk can deliver up to 1,000,000 IOPS, a maximum throughput of 4 GB/s, and a maximum performance density of 1,000 IOPS per GiB.
Scenarios
In addition to the scenarios for which ESSDs are suitable, such as latency-sensitive applications and I/O-intensive workloads, ESSD AutoPL disks are suitable for the following scenarios:
Scenarios in which disk performance needs to be increased without extending disk capacity.
Scenarios in which business workloads greatly fluctuate and require disks to burst their performance in response to workload spikes.
Disk specifications
The following table describes the specifications of ESSD AutoPL disks.
Performance level | Disk attribute | Specifications |
Baseline performance | Capacity range (GiB) | 1 to 65,536 |
Maximum IOPS per disk | 50,000 | |
Maximum I/O size (KB) | 16 | |
Maximum throughput per disk (MB/s) | 350 | |
Average random write latency per connection (ms) | 0.2 | |
Formula used to calculate IOPS per disk (baseline IOPS①) | max{min{1,800 + 50 × Capacity, 50,000}, 3,000} | |
Formula used to calculate throughput per disk (baseline throughput①, MB/s) | max{min{120 + 0.5 × Capacity, 350}, 125} | |
Provisioned performance | Maximum provisioned IOPS② per disk | 50,000 |
Formula used to calculate IOPS per disk (provisioned IOPS②) | Capacity (GiB) <= 3: not configurable Capacity (GiB) >= 4: [1, min{(1,000 IOPS per GiB × Capacity - Baseline IOPS), 50,000}] | |
Formula used to calculate throughput per disk (provisioned throughput②, MB/s) | 16 KB × Provisioned IOPS/1,024 | |
Burst performance | Formula used to calculate the burst IOPS per disk (burst IOPS③) | Ultimate IOPS - Baseline IOPS - Provisioned IOPS |
Formula used to calculate the burst throughput per disk (burst throughput③, MB/s) | Ultimate throughput - Baseline throughput - Provisioned throughput | |
Performance of an ESSD AutoPL disk | Performance composition | Baseline performance① + Provisioned performance② + Burst performance③ |
Maximum I/O density per disk④ | 1,000 IOPS/GiB | |
Maximum IOPS per disk with the performance burst feature enabled | Capacity <= 3 GiB: The performance burst feature cannot be enabled. Capacity >= 4 GiB: min{1,000,000, 1,000 × Capacity} | |
Maximum throughput per disk with the performance burst feature enabled | Capacity <= 3 GiB: The performance burst feature cannot be enabled. Capacity >= 4GiB: max{min{16 KB × IOPS/1,024, 4 GB/s}, (Baseline throughput + Provisioned throughput)} | |
Maximum IOPS per disk with the performance burst feature disabled (The value is the sum of the baseline IOPS per disk and the maximum provisioned IOPS per disk.) | 100,000 | |
Maximum throughput per disk with the performance burst feature disabled (The value is the sum of the baseline throughput per disk and the maximum provisioned throughput per disk.) | 1,131 MB/s |
①: indicates the baseline performance that an ESSD AutoPL disk can deliver, excluding provisioned performance and burst performance.
②: indicates the provisioned performance that an ESSD AutoPL disk can deliver in addition to baseline performance.
③: indicates the burst performance that an ESSD AutoPL disk can deliver, in addition to baseline performance and provisioned performance. You can use CloudLens for EBS of Elastic Block Storage (EBS) to monitor the performance burst details of an ESSD AutoPL disk in real time, including the burst duration and the number of performance bursts. For more information, see the "View the burst performance data of an ESSD AutoPL disk" section of the Analyze disks topic.
④: I/O density = Number of IOPS/Disk capacity. Unit: IOPS per GiB.
The read/write performance of disks is limited by instance types and disk specifications and cannot exceed any of the limits specified by the instance types or disk specifications. For example, if the maximum disk bandwidth allowed for an instance type is 6 Gbit/s, which can be converted to 750 MB/s, the throughput of each disk on an instance of the instance type cannot exceed 750 MB/s.
For information about the disk IOPS and bandwidth supported by different instance types, see Overview of instance families. If a disk cannot deliver its maximum performance due to the limits of an instance type, we recommend that you upgrade the instance type.
For information about the relationship between instance types and storage I/O performance, see the Relationship between instance types and storage I/O performance section of the "Storage I/O performance" topic.
Supported instance families
ESSD AutoPL disks support the same instance families as ESSDs. For information about instance families, see Overview of instance families.
Billing
Billable items and billing rules
You are charged disk capacity fees, provisioned performance fees, and burst performance fees for ESSD AutoPL disks. For information about the billing rules of ESSD AutoPL disks, see Block storage devices.
Disk capacity fees: You are charged for the disk capacity of each ESSD AutoPL disk. The baseline performance of an ESSD AutoPL disk is equal to the baseline performance of an ESSD at performance level 1 (PL1 ESSD) that has the same capacity as the ESSD AutoPL disk.
Provisioned performance fees: You are charged for the provisioned performance of ESSD AutoPL disks based on the pay-as-you-go billing method.
Burst performance fees: You are charged for the burst performance of ESSD AutoPL disks based on the pay-as-you-go billing method.
Total number of burst I/Os per hour <= 100,000: All I/O bursts are covered by a free quota of 100,000 burst I/Os. You are not charged burst performance fees.
Total number of burst I/Os per hour > 100,000: Fee cap rules apply to keep the fees that are imposed on burst I/Os bounded. This way, you can achieve high performance without the need to worry about excessive burst performance fees. For more information, see the Burst performance fee cap rules section of this topic.
Burst performance fee cap rules
In extreme business scenarios, a higher-than-expected number of burst IOPS may result in excessive burst performance fees. To resolve the preceding issue, burst performance fee cap rules are applied to ESSD AutoPL disks to limit burst performance fees within a controllable range even in extreme cases.
Fee cap rules
A fee cap rule is triggered to limit burst performance fees when the maximum burst I/O density exceeds 200 IOPS per GiB. The maximum burst I/O density is calculated by using the following formula: Maximum burst IOPS/Disk capacity. The following table describes the burst performance fee cap rules.
NoteBurst IOPS excludes the baseline IOPS and the provisioned IOPS.
Total number of burst I/Os (I/Os per hour)
Maximum burst I/O density (IOPS per GiB)
Fee not capped
Fee capped
Common scenario
Up to 100,000
N/A
Fee = Total number of burst I/Os × Unit price of performance bursts. The price of performance bursts is measured in USD per 10,000 I/Os.
No fee (free quota of 100,000 burst I/Os)
I/O glitches occasionally occur.
Greater than 100,000
Up to 200
Not capped
Fee = (Number of burst I/Os - 100,000) × Unit price of performance bursts. The price of performance bursts is measured in USD per 10,000 I/Os.
Business spikes occasionally occur, but the number of burst IOPS does not exceed the threshold for limiting burst performance fees.
Greater than 200
Capped
Fee = min((Number of burst I/Os - 100,000) × Unit price of performance bursts, Disk capacity fee × 8). The price of performance bursts is measured in USD per 10,000 I/Os.
Disks are under extreme workload that requires high IOPS for an extended period of time.
Billing examples for cost savings
For example, in the China (Hangzhou) region, a 40 GiB ESSD AutoPL disk bursts its performance for 1 hour while the disk is being used. The total number of burst I/Os during the hour is 4,390,000, and the maximum burst I/O density during the hour is 230 IOPS per GiB, which triggers the burst performance fee cap rule to limit the burst performance fees. The following table describes the comparison between the burst performance fees before being capped and the burst performance fees after being capped.
Item
Formula
Burst performance fee
Burst performance fees before being limited
Total number of burst I/Os × Unit price of performance bursts. The price of performance bursts is measured in USD per 10,000 I/Os.
4,390,000 × 0.0015/10,000= USD 0.6585
Burst performance fees after being limited
min ((Number of burst I/Os - 100,000) × Unit price of performance bursts, Disk capacity fee × 8). The price of performance bursts is measured in USD per 10,000 I/Os.
min((4,390,000 - 100,000) × 0.0015/10,000, 8 × 40 × 0.000319) = USD 0.1021
You can go to the Expenses and Costs console to view the burst performance fees and the billing details of ESSD AutoPL disks. For more information, see View billing details.
Pricing
For information about the pricing of ESSD AutoPL disks, see the Pricing tab of the Elastic Compute Service (ECS) product page.
Impacts of overdue payments
If your Alibaba Cloud account has overdue payments for the provisioned performance and the burst performance of ESSD AutoPL disks, Alibaba Cloud stops providing the performance provision feature and the performance burst feature for ESSD AutoPL disks. The baseline performance of the ESSD AutoPL disks is not affected. If you want to continue using the performance provision feature and the performance burst feature for the ESSD AutoPL disks, you must complete the overdue payments. After you complete the overdue payments, the performance provision feature and the performance burst feature become available for the ESSD AutoPL disks.
Configure the provisioned performance and the burst performance of an ESSD AutoPL disk
You can create an ESSD AutoPL disk separately or together with an ECS instance in the ECS console based on your business requirements.
For information about how to create an ECS instance and create a disk, see Create an instance on the Custom Launch tab and Create an empty data disk.
After you create an ESSD AutoPL disk, you can configure the performance provision feature and the performance burst feature for the disk based on your business requirements to reduce costs. For more information, see Modify the performance configurations of an ESSD AutoPL disk.
In the following example, an ESSD AutoPL disk is separately created in the ECS console. Perform the following steps:
Log on to the ECS console.
In the left-side navigation pane, choose .
In the top navigation bar, select the region and resource group to which the resource belongs.
On the Cloud Disk tab of the Block Storage page, click Create Cloud Disk.
On the Cloud Disk page, configure parameters of the ESSD AutoPL disk.
In the Storage section, select ESSD AutoPL Disk as the disk category and specify a disk capacity.
Select Enable Performance Provision to enable the performance provision feature for the disk and specify a provisioned IOPS value.
By default, Enable Performance Burst is selected. You can disable the performance burst feature based on your business requirements.
For information about how to configure other parameters on the Cloud Disk page, see Create an empty data disk.
Billing examples of an ESSD AutoPL disk
The following section provides examples of how an ESSD ESSD AutoPL disk is billed after you enable the performance provision and performance burst features. The following section also describes the performance metrics of the disk. In the following examples, the China (Hangzhou) region is used. The following unit prices apply to the region:
Subscription
Unit price of baseline performance: USD 0.153 per GiB per month
Unit price of provisioned performance: USD 0.000006 per IOPS per hour
Unit price of performance bursts: USD 0.0015 per 10,000 I/Os
Pay-as-you-go
Unit price of baseline performance: USD 0.000319 per GiB per hour
Unit price of provisioned performance: USD 0.000006 per IOPS per hour
Unit price of performance bursts: USD 0.0015 per 10,000 I/Os
The preceding unit prices are for reference only. The actual prices displayed on the Pricing tab of the Elastic Compute Service product page prevail.
Example 1:
When you purchased an ESSD AutoPL disk in the ECS console, you set the disk capacity to 100 GiB and the provisioned performance to 200 IOPS, and disabled the performance burst feature. The following table describes the fees and performance of the disk.
Billing method | Disk fee (USD) | Disk performance |
Subscription
Subscription duration: 1 month |
|
|
Pay-as-you-go
Billing duration: 24 hours |
|
Example 2:
When you purchased an ESSD AutoPL data disk in the ECS console, you set the disk capacity to 100 GiB and the provisioned performance to 200 IOPS. By default, the performance burst feature is enabled. 
The fees and performance of the ESSD AutoPL disk vary based on the performance burst scenario. Examples:
Scenario 1: Only burst IOPS is generated.
Assume that the IOPS bursts only once for 1 second during disk usage. The number of I/O bursts that exceed the sum of the baseline I/Os and the provisioned I/Os is 8,000, which is covered by a free quota of 100,000 I/Os per hour, and the burst performance fee is USD 0.
Billing method
Disk fee (USD)
Disk performance
Subscription
Baseline performance: subscription
Provisioned performance: pay-as-you-go
Performance burst: pay-as-you-go
Subscription duration: 1 month
Baseline performance fee: Disk capacity × Unit price per disk × Subscription duration = 100 × 0.153 × 1 = USD 15.3.
Provisioned performance fee: Unit price of provisioned performance × Provisioned IOPS × Subscription duration = 0.000006 × 200 × (30 × 24) = USD 0.864.
Burst performance fee: I/O bursts are covered by a free quota of 100,000 burst I/Os. You are not charged burst performance fees.
Total fee: Baseline performance fee + Provisioned performance fee + Burst performance fee = 15.3 + 0.864 + 0 = USD 16.164.
IOPS:
Baseline IOPS: 1,800 + 50 × Capacity = 1,800 + 50 × 100 = 6,800 IOPS
Provisioned IOPS: 200 IOPS
Burst IOPS: 8,000 × 1 = 8,000 IOPS
Total IOPS per disk: Baseline IOPS + Provisioned IOPS + Burst IOPS = 6,800 + 200 + 8,000 = 15,000 IOPS
Throughput (MB/s):
Baseline throughput: 120 + 0.5 × Capacity = 120 + 0.5 × 100 = 170 MB/s
Provisioned throughput: 16 KB × Provisioned IOPS/1,024 = 16 KB × 200/1,024 = 3.125 MB/s
Total throughput per disk: Baseline throughput + Provisioned throughput = 170 + 3.125 = 173.125 MB/s (rounded to 173, which is displayed in the ECS console)
Pay-as-you-go
Baseline performance: pay-as-you-go
Provisioned performance: pay-as-you-go
Performance burst: pay-as-you-go
Billing duration: 24 hours
Baseline performance fee: Disk capacity × Unit price per disk × Billing duration = 100 × 0.000319 × 24 = USD 0.7656.
Provisioned performance fee: Unit price of provisioned performance × Provisioned IOPS × Billing duration = 0.000006 × 200 × 24 = USD 0.0288.
Burst performance fee: I/O bursts are covered by a free quota of 100,000 burst I/Os. You are not charged burst performance fees.
Total fee: Baseline performance fee + Provisioned performance fee + Burst performance fee = 0.7656 + 0.0288 + 0 = USD 0.7944.
Scenario 2: Burst throughput is generated, but burst IOPS is not generated.
Assume that the throughput bursts only once for 28 seconds during disk usage. The burst throughput that exceeds the sum of the baseline throughput and provisioned throughput is 1 GB/s, which is converted to the number of burst I/Os (1 × 1,024 × 1,024/16 = 65,536). Then, the number of burst I/Os of the throughput within 28 seconds is equal to 1,835,008 (65,536 × 28 = 1,835,008). The number is rounded up to 1,840,000 I/Os for billing. If the total number of burst I/Os is greater than 100,000 and the I/O density is greater than 200 IOPS per GiB, the burst performance fee cap rule is triggered. Maximum burst I/O density = 65,536/100 = 655.36 IOPS per GiB.
Billing method
Disk fee (USD)
Disk performance
Subscription
Baseline performance: subscription
Provisioned performance: pay-as-you-go
Performance burst: pay-as-you-go
Subscription duration: 1 month
Baseline performance fee: Disk capacity × Unit price per disk × Subscription duration = 100 × 0.153 × 1 = USD 15.3.
Provisioned performance fee: Unit price of provisioned performance × Provisioned IOPS × Subscription duration = 0.000006 × 200 × (30 × 24) = USD 0.864.
Burst performance fee: min((Number of burst I/Os - 100,000) × Unit price of performance bursts, Disk capacity fee × 8) = min((1840,000 - 100,000) × 0.0015/10,000, 0.000319 × 100 × 8) = USD 0.2552.
Total fee: Baseline performance fee + Provisioned performance fee + Burst performance fee = 15.3 + 0.864 + 0.2552 = USD 16.4192.
IOPS:
Baseline performance IOPS: 1,800 + 50 × Capacity = 1,800 + 50 × 100 = 6,800 IOPS
Total IOPS per disk: Baseline IOPS + Provisioned IOPS = 6,800 + 200 = 7,000 IOPS
Throughput (MB/s):
Baseline throughput: 120 + 0.5 × Capacity = 120 + 0.5 × 100 = 170 MB/s
Provisioned throughput: 16 KB × Provisioned IOPS/1,024 = 16 KB × 200/1,024 = 3.125 MB/s
Burst throughput: 1 GB/s × 1,024 = 1,024 MB/s
Total throughput per disk: Baseline throughput + Provisioned throughput + Burst throughput = 170 + 3.125 + 1,024 = 1,197.125 MB/s
Pay-as-you-go
Baseline performance: pay-as-you-go
Provisioned performance: pay-as-you-go
Performance burst: pay-as-you-go
Billing duration: 24 hours
Baseline performance fee: Disk capacity × Unit price per disk × Billing duration = 100 × 0.000319 × 24 = USD 0.7656.
Provisioned performance fee: Unit price of provisioned performance × Provisioned IOPS × Billing duration = 0.000006 × 200 × 24 = USD 0.0288.
Burst performance fee: min((Number of burst I/Os - 100,000) × Unit price of performance bursts, Disk capacity fee × 8) = min((1,840,000 - 100,000) × 0.0015/10,000, 0.000319 × 100 × 8) = USD 0.2552.
Total fee: Baseline performance fee + Provisioned performance fee + Burst performance fee = 0.7656 + 0.0288 + 0.2552 = USD 1.0496.
Scenario 3: Burst IOPS and burst throughput are both generated, and you are charged based on the larger number of burst I/Os.
Assume that burst IOPS and burst throughput are generated once for 2 seconds during disk usage. The burst IOPS is 8,000, and the burst throughput is 1 GB/s. The number of burst IOPS within 2 seconds is 16,000 (8,000 × 2 = 16,000). The number of burst I/Os of the burst throughput within 2 seconds is 131,072 (1 × 1,024 × 1,024/16 × 2 = 131,072), which is rounded up to 140,000. Then, the burst performance fee is calculated based on 140,000 I/Os. If the total number of burst I/Os is greater than 100,000 and the I/O density is greater than 200 IOPS per GiB, the burst performance fee cap rule is triggered. The maximum burst I/O density = 65,536/100 = 655.36 IOPS per GiB.
Billing method
Disk fee (USD)
Disk performance
Subscription
Baseline performance: subscription
Provisioned performance: pay-as-you-go
Performance burst: pay-as-you-go
Subscription duration: 1 month
Baseline performance fee: Disk capacity × Unit price per disk × Subscription duration = 100 × 0.153 × 1 = USD 15.3.
Provisioned performance fee: Unit price of provisioned performance × Provisioned IOPS × Subscription duration = 0.000006 × 200 × (30 × 24) = USD 0.864.
Burst performance fee: min((Number of burst I/Os - 100,000) × Unit price of performance bursts, Disk capacity fee × 8) = min((140,000 - 100,000) × 0.0015/10,000, 0.000319 × 100 × 8) = USD 0.006.
Total fee: Baseline performance fee + Provisioned performance fee + Burst performance fee = 15.3 + 0.864 + 0.006 = USD 16.17.
IOPS:
Baseline IOPS: 1,800 + 50 × Capacity = 1,800 + 50 × 100 = 6,800 IOPS
Provisioned IOPS: 200 IOPS
Burst IOPS: 8,000 × 1 = 8,000 IOPS
Total IOPS per disk: Baseline IOPS + Provisioned IOPS + Burst IOPS = 6,800 + 200 + 8,000 = 15,000 IOPS
Throughput (MB/s):
Baseline throughput: 120 + 0.5 × Capacity = 120 + 0.5 × 100 = 170 MB/s
Provisioned throughput: 16 KB × Provisioned IOPS/1,024 = 16 KB × 200/1,024 = 3.125 MB/s
Burst throughput: 1 GB/s × 1,024 = 1,024 MB/s
Total throughput per disk: Baseline throughput + Provisioned throughput + Burst throughput = 170 + 3.125 + 1,024 = 1,197.125 MB/s
Pay-as-you-go
Baseline performance: pay-as-you-go
Provisioned performance: pay-as-you-go
Performance burst: pay-as-you-go
Billing duration: 24 hours
Baseline performance fee: Disk capacity × Unit price per disk × Billing duration = 100 × 0.000319 × 24 = USD 0.7656.
Provisioned performance fee: Unit price of provisioned performance × Provisioned IOPS × Billing duration = 0.000006 × 200 × 24 = USD 0.0288.
Burst performance fee: min((Number of burst I/Os - 100,000) × Unit price of performance bursts, Disk capacity fee × 8) = min((140,000 - 100,000) × 0.0015/10,000, 0.000319 × 100 × 8) = USD 0.006.
Total fee: Baseline performance fee + Provisioned performance fee + Burst performance fee = 0.7656 + 0.0288 + 0.006 = USD 0.8004.