Storage capacity units (SCUs) are subscription storage resource plans that can be used to offset the pay-as-you-go bills of various storage resources. Compared with disks purchased together with subscription Elastic Compute Service (ECS) instances or resource plans of a specific resource, SCUs offer a better combination of cost-effectiveness and flexibility together with pay-as-you-go resources.
Offset rules
SCUs can be used to offset the storage fees of multiple Alibaba Cloud storage services. The following table describes the rules that apply when you use SCUs to offset the storage fees of different cloud disks in regions inside the Chinese mainland.
For information about the rules that are applied to other Alibaba Cloud storage services and regions, visit the Pricing tab of the Elastic Compute Service product page.
Type | Deduction factor | Description |
Basic disk | 1 | Each GiB of basic disk space consumes 1 GiB of SCU capacity. |
Ultra disk | 1 | Each GiB of ultra disk space consumes 1 GiB of SCU capacity. |
Standard SSD | 1 | Each GiB of standard SSD space consumes 1 GiB of SCU capacity. |
PL0 enhanced SSD (ESSD) | 0.5 | Each GiB of PL0 ESSD space consumes 0.5 GiB of SCU capacity. |
PL1 ESSD | 1 | Each GiB of PL1 ESSD space consumes 1 GiB of SCU capacity. |
PL2 ESSD | 2 | Each GiB of PL2 ESSD space consumes 2 GiB of SCU capacity. |
PL3 ESSD | 4 | Each GiB of PL3 ESSD space consumes 4 GiB of SCU capacity. |
Examples
If you purchase a 10 TiB SCU and use only cloud disks, the SCU can be applied to different combinations of disk categories:
Combination 1:
PL1 ESSDs: The SCU can be used to offset the bills for 10 TiB of PL1 ESSDs.
Combination 2:
PL0 ESSDs and PL1 ESSDs: The SCU can be used to offset the bills for 10 TiB of PL0 ESSDs and 5 TiB of PL1 ESSDs.
Combination 3
PL1 ESSD, PL2 ESSDs, and PL3 ESSDs: The SCU can be used to offset the bills for the 1 TiB of PL3 ESSDs, 2 TiB of PL2 ESSDs, and 2 TiB of PL1 ESSDs.
Combination 4
Standard SSD: For standard SSDs that are 12 TiB in size, the SCU can be used to offset the bills for 10 TiB of standard SSDs, and you are charged for the remaining 2 TiB at the regular pay-as-you-go rate.