Overview

There are yearly/monthly and pay-per-use billing modes. Each one has different advantages and disadvantages.

• Yearly/Monthly is a prepaid billing. You pay in advance for a subscription term, and in exchange, you get a discounted rate. The longer the subscription term, the bigger the discount. Yearly/Monthly billing is a good option for long-term, stable services.
• Pay-per-use is a postpaid billing mode. You pay as you go and just pay for what you use. There are no wasted resources.
  Table 1 lists the differences between the billing modes.

  Table 1 Differences between billing modes

  Billing Mode	Yearly/Monthly	Pay-per-Use
  Payment	Prepaid	Postpaid
  Billing Method	Billed by the subscription term you purchase	Billed by the hour
  Billed Items	SFS Turbo (excluding HPC Cache file systems)	SFS Capacity-Oriented and SFS Turbo
  Changing the Billing Mode	Yearly/Monthly can be changed to pay-per-use. Pay-per-use billing takes effect only after the yearly/monthly subscription ends. Yearly/Monthly to Pay-per-Use	Pay-per-use can be changed to yearly/monthly. Pay-per-Use to Yearly/Monthly
  Changing the File System Type	Not supported	Not supported
  Changing the File System Capacity	Supported File system capacity cannot be reduced. File system capacity can be expanded, and you need to pay for the price difference. The file system expiration time remains unchanged after an expansion.	Supported File system capacity cannot be reduced. File system capacity can be expanded. Additional capacities are billed on a pay-per-use basis.
  Application Scenarios	Recommended for resources expected to be in use long-term. A cost-effective option for scenarios where the resource usage duration is predictable.	Recommended when the resource demands are likely to fluctuate and you want more flexibility.