Storage capacity units (SCUs) are subscription storage resource plans that can be used to offset the storage fees of various Alibaba Cloud storage services.
Offset rules
SCUs can be used to offset the storage fees of various Alibaba Cloud storage services. The following table describes the rules that take effect when you use SCUs to offset the storage fees of Apsara File Storage NAS (NAS) in regions in the Chinese mainland.
For more information about the rules that apply to other Alibaba Cloud storage services and regions, visit the pricing page.
File system type | Offset coefficient | Description |
Capacity NAS file system | 0.25 | You can use 0.25 GiB of capacity in your SCU to offset the fee for 1 GiB of storage usage from a Capacity NAS file system. |
Performance NAS file system | 0.89 | You can use 0.89 GiB of capacity in your SCU to offset the fee for 1 GiB of storage usage from a Performance NAS file system. |
Offset order
The storage usage fees of NAS are offset in the following order: storage plans, resource plans, and SCUs. You are charged for the remaining usage based on the pay-as-you-go billing method.
Examples
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 | 500 GiB of capacity in the resource plan offsets the fee for 500 GiB of storage usage from the Capacity NAS file system. | 25 GiB of capacity in the SCU offsets the fee for 100 GiB of storage usage from the Capacity NAS file system. 25 GiB indicates the capacity in the SCU used to offset the fee for the remaining 100 GiB of storage usage from the Capacity NAS file system, in addition to the 500 GiB of capacity in the resource plan used to offset the fee for 500 GiB of storage usage from the Capacity NAS file system. Calculation formula: (600 GiB - 500 GiB) × 0.25 = 25 GiB |