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Burst performance billing - ESSD FlexPL volumes

After enabling burst performance for your ESSD FlexPL volumes, you will be charged based on your usage. This topic explains the billing rules and notes regarding performance bursts on ESSD FlexPL volumes.

tip

This feature is currently in closed beta. Please contact your account manager for access.

IOPS-based billing

Performance bursts on ESSD FlexPL volumes are billed hourly based on the number of burst IOPS. The calculation varies by scenario. Specifically:

Scenario	Billing rules
IOPS burst only	Use the actual burst IOPS. Formula: Burst IOPS for a given hour= ∑ Burst IOPS × Burst duration
Throughput burst only	Convert burst throughput to equivalent IOPS and then calculate the burst IOPS. Formula: Equivalent IOPS = Burst throughput (MB/s) × 1,024 ÷ 16 Burst IOPS for a given hour = ∑ Burst throughput (MB/s) × 1,024 ÷ 16 × Burst duration
Bursts of both throughput and IOPS	Convert the burst throughput into equivalent IOPS and then compare the equivalent IOPS with the burst IOPS. Use the larger of the two for billing. Formula: Equivalent IOPS = Burst throughput (MB/s) × 1,024 ÷ 16

Capped billing

To prevent high costs during traffic spikes, EBS employs a cap on burst costs. This keeps expenses manageable. When the IOPS density for a given hour exceeds 200, EBS compares the actual burst cost to the capped cost and charges the lower amount. The capped burst cost is calculated as follows:

Volume capacity × Unit price × 8

Burst IOPS for a given hour	Performance density	Formula
< 100,000	Not applicable	100,000 burst IOPS per hour for free
> 100,000	IOPS density for the hour ≤ 200	Burst cost for the hour = (Burst IOPS for the hour – 10) × Unit price
> 100,000		IOPS density for the hour > 200	Burst cost for the hour = min((Burst IOPS for the hour – 10) × Unit price, Volume capacity × Unit price × 8)

tip

IOPS density is calculated as follows: IOPS density for a given hour = Burst IOPS for the hour ÷ Volume capacity.

Billing method

Burst performance is billed on a pay-as-you-go basis only. Subscription billing is not supported.

Billing method	Formula (¥/IOPS/hour)	Notes
Pay-as-you-go	Cost = Unit price × IOPS for a given hour. Unit price is 0.02 CNY per 10,000 IOPS.	A free quota of 100,000 IOPS per hour is provided for each volume. Burst performance is free when the burst IOPS for a given hour is less than or equal to 100,000. If the burst IOPS for a given hour exceeds 100,000, capped billing applies. To help control costs, the hourly maximum cost is calculated as follows: Volume capacity × Unit price × 8.

Examples

Scenario 1: IOPS burst only

Assume that, between 9:00:00 and 10:00:00 on September 1, 2025, a 500 GiB volume experiences a two-second IOPS burst with no throughput burst. The burst IOPS beyond the baseline and additional IOPS is 10,000.

Burst IOPS for the 9:00:00–10:00:00 hour: 10,000 × 2 = 20,000. Each volume has a free quota of 100,000 burst IOPS per hour. Since the number of burst IOPS does not exceed the free quota, the burst cost for the hour is zero.

Scenario 2: Throughput burst only

Assume that, between 9:00:00 and 10:00:00 on September 1, 2025, a 500 GiB volume experiences a 60-second throughput burst with no IOPS burst. The burst throughput beyond the baseline and additional throughput is 1,500 MB/s.

Burst throughput = 1,500 × 60 = 90,000 MB.

Equivalent IOPS (converting throughput to IOPS)= 90,000 × 1,024 ÷ 16 = 5,760,000.

Acutal burst cost = (5,760,000 ÷ 10,000 – 10) × 0.02 = ¥11.32.

IOPS density for the hour = 5,760,000 ÷ 500 = 11,520 IOPS/GiB. The performance density exceeds 200 IOPS/GiB. Therefore, capped billing applies. Capped burst cost: 500 × 0.0021 × 8 = ¥8.4.

Since the actual burst cost is higher than the capped cost, the cost for the hour is capped at ¥8.4.

Scenario 3: Bursts of both throughput and IOPS (billed based on the larger of the two)

Assume that a 500 GiB volume experiences bursts of IOPS and throughput from 9:00:00 to 10:00:00 on September 1, 2025. The burst IOPS is 20,000 and the burst throughput is 1,000 MB/s. Each burst lasts 10 seconds.

Burst IOPS: 20,000 × 10 = 200,000.

Converting burst throughput to equivalent IOPS: Burst throughput (MB) = 1,000 × 10 = 10,000 MB; Equivalent IOPS = 10,000 × 1,024 ÷ 16 = 640,000. Since the equivalent IOPS (640,000) is greater than the burst IOPS (200,000), burst performance is billed based on the equivalent IOPS.

Actual burst cost: (640,000 ÷ 10,000 – 10) × 0.02 = (64 – 10) × 0.02 = ¥1.08.

IOPS density for the hour = 640,000 ÷ 500 = 1,280 IOPS/GiB. The performance density exceeds 200 IOPS/GiB. Therefore, capped billing applies. Capped burst cost: 500 × 0.0021 × 8 = ¥8.4.

Since the actual burst cost is lower than the capped cost, the cost for the hour is ¥1.08.

Last updated: 2026.06.24 14:50:51