A storage capacity unit (SCU) is a type of subscription billing method. You can purchase multiple SCUs and use them to offset the pay-as-you-go bills of multiple Alibaba Cloud storage services.
Purchase SCUs
To learn how to purchase an SCU, see Purchase an SCU.
Offset rules
SCUs can be used to offset the storage usage fees of various Alibaba Cloud storage services. The following table describes the offset coefficients when you use SCUs to offset the storage usage fees of each type of NAS file system in regions in the Chinese mainland.
For more information about the offset coefficients for other Alibaba Cloud storage services and in other regions, see Product Pricing.
|
File system type |
Offset coefficient |
Description |
|
General-purpose CapacityNAS |
0.35 |
Every0.35 GiB SCUcapacity can offset1 GiBGeneral-purpose CapacityNASusage。 |
|
General-purpose PerformanceNAS |
1.85 |
Every1.85 GiB SCUcapacity can offset1 GiBGeneral-purpose PerformanceNASusage。 |
Offset order
The following figure shows the order in which the storage usage fees of NAS file systems are offset.
Example
You purchased a General-purpose NAS resource plan of 500 GiB and an SCU of 100 GiB in the China (Beijing) region in January 2021. In February 2021 in the China (Beijing) region, the storage usage of a Capacity NAS file system is 600 GiB per hour. The following table describes how the resource plan and the SCU offset the monthly usage fees of the file systems.
|
File system type |
Offset by the resource plan |
Offset by the SCU |
|
Capacity NAS file system |
The 500 GiB general-purpose NAS resource plan offsets the fees for 500 GiB of storage for the capacity NAS file system. |
The SCU uses 35 GiB to offset the fees for the remaining 100 GiB of storage for the capacity NAS file system. The remaining 100 GiB of storage consumes 35 GiB of SCU capacity. Calculation: (600 GiB - 500 GiB) × 0.35 = 35 GiB. |