This topic describes the billable items, billing cycle, and billing methods of General-purpose NAS file systems. This topic also compares the billing methods and provides several billing examples.

Billable items

Billable item Description
Storage usage The maximum storage space that is used in the file system. Fees are calculated per hour based on the maximum storage space.
  • The used storage space is the total size of all files in a file system. The size of directories is not included. The basic storage unit is 4 KiB. If the size of a file is less than 4 KiB, the billed storage space of the file is rounded up to 4 KiB. If the size of a file is larger than 4 KiB, the billed storage space is rounded up to the nearest multiple of 4 KiB. For example, if the size of a file is 2 KiB, the system counts the size of the file as 4 KiB. If the size of a file is 6KiB, the system counts the size of the file as 8 KiB.
  • File holes occupy storage space in a NAS file system. You are charged for the file holes in your NAS file system. A file hole consists of zeros that are not written to a file. You can create a file hole by using the truncate, lseek, or fallocate command.
  • After you enable the recycle bin feature, you are charged for the storage usage of the temporary files in the recycle bin based on the pricing of the original storage class during the retention period. For example, after you delete a file from a Capacity NAS file system, you are charged for the file based on the unit price of storage space in Capacity NAS file systems. After you delete a file from an IA storage medium, you are charged for the file based on the unit price of storage space in the IA storage medium. For more information, see Enable a recycle bin.

Billing cycle

The fees for each hour are deducted from your account balance the next hour. For example, you are billed at 09:30 for the fees that are incurred from 08:00 to 09:00.

Note If you receive a bill at 09:30, the bill may include fees that are incurred from 07:00 to 08:00 due to system latency.

Comparison of billing methods

After you create an Apsara File Storage NAS file system, you are billed based on the pay-as-you-go billing method by default. You can purchase resource plans and storage capacity units (SCUs) to offset fees. The following table compares the operations and billable items that are supported by each billing method. A check (✓) sign indicates that the operation is supported by the billing method. A cross (×) sign indicates that the operation is not supported by the billing method. A hyphen (-) sign indicates that the operation is not applicable to the billing method.
Billing method Billable item Purchase Offset the storage usage fees of General-purpose NAS file systems of different storage classes Offset the storage usage fees of multiple NAS file systems Offset only the storage usage fees of NAS file systems Renew Upgrade Purchase multiple at a time
Pay-as-you-go All billable items of NAS file systems - - - - - - -
Resource plan
  • Storage usage of General-purpose NAS file systems
  • Storage usage of IA storage media
Yes
Storage plan
  • Storage usage of General-purpose NAS file systems
  • Storage usage of IA storage media
× × × ×
SCU Storage usage of General-purpose NAS file systems × × ×
If you have resource plans, SCUs, and storage plans associated with your Alibaba Cloud account, the storage usage fees are offset in the following order: storage plans, resource planes, and then you are charged based on the pay-as-you-go billing method.

Billing method

  • Pay-as-you-go

    After you activate Apsara File Storage NAS, you are charged based on the pay-as-you-go billing method by default.

    The storage usage fee is calculated by using the following formula: Storage usage fee = Maximum usage of a NAS file system per hour × Unit price per hour.
    Note
    • You can log on to the NAS console to view the storage usage in the Basic Information section. The storage usage is updated once per hour. Due to latency, the storage usage displayed in the console at the current local time may be the storage usage of the previous hour.
    • General-purpose NAS file systems are divided into two types: Capacity NAS file system and Performance NAS file system. Both types have different unit prices for storage usage. For NAS file systems, the unit of storage usage fee is USD/GiB/month. When the storage usage fee is calculated, the unit of measurement is converted to USD/GiB /hour. For more information, see Apsara File Storage NAS pricing.
  • Resource plans (recommended)

    A resource plan can be used to reduce the cost of resources. You can purchase multiple resource plans at the same time and use them to offset the storage usage fees of multiple file systems. Resource plans are applied based on the following order: Performance NAS file systems, Capacity NAS file systems, and IA storage media.

    • Purchase method

      For more information about how to purchase a storage plan, see Manage storage plans.

    • Deduction rules
      The following table describes rules that apply when you use resource plans to offset the storage usage of different storage classes of NAS file systems in mainland China. To learn how rules are applied in other regions, you can use the calculator feature to view the relevant information.
      Storage class Conversion coefficient Description
      Capacity NAS file system 1 You can use 1 GiB of base capacity in your General-purpose resource plan to offset 1 GiB of storage usage from a Capacity NAS file system.
      Performance NAS file system 5.47 You can use 5.47 GiB of base capacity in your General-purpose resource plan to offset 1 GiB of storage usage from a Performance NAS file system.
      IA storage medium 0.37 You can use 0.37 GiB of base capacity in your General-purpose resource plan to offset 1 GiB of storage usage from an IA storage medium.
      You can use the calculator feature provided by Alibaba Cloud to calculate the deductions of the resource plans within your account in the current region. This way, you can select appropriate resource plans based on the current storage usage to reduce your costs.
    • Renewal and upgrade

      You can renew and upgrade a resource plan. For more information, see Manage resource plans.

  • SCUs

    An SCU is a type of subscription billing method. You can purchase multiple SCUs at the same time and use them to offset the storage usage fees of multiple Alibaba Cloud storage services. SCUs are more flexible and cost-effective than storage plans that are dedicated to specific storage services.

    • Purchase method

      For more information about how to purchase SCUs, see Create an SCU.

    • Deduction rules
      You can use SCUs to offset the storage usage fees of NAS, OSS, and ECS resources. The following table describes the rules that apply when you use SCUs to offset the storage usage fees of different storage classes of NAS file system in mainland China. For more information about the rules for other Alibaba Cloud storage services and regions, visit the Pricing page.
      File system type Deduction factor Description
      Capacity NAS file system 0.25 You can use 0.25 GB of capacity in your SCU to offset 1 GB of storage usage from a Capacity NAS file system.
      Performance NAS file system 0.889 You can use 0.889 GB of capacity in your SCU to offset 1 GB of storage usage from a Performance NAS file system.
  • Storage plans

    A storage plan is a type of subscription billing method. You can use a storage plan to offset only the storage usage fees of a file system to which the storage plan is attached.

    Notice Alibaba Cloud supports resource plans for Apsara File Storage NAS. You can no longer purchase storage plans. However, you can renew or upgrade existing storage plans. Compared with a storage plan, a resource plan does not need to be bound to a file system. You can purchase multiple resource plans to offset the storage usage fees of multiple file systems.
    • Deduction rules
      • After you purchase a storage plan, NAS offsets fees from the storage plan based on the storage usage of your file system.
      • You can attach a storage plan to only one General-purpose NAS file system at the same time. If you delete the General-purpose NAS file system, its storage plan is automatically detached. However, the detached storage plan can be attached to another file system of the same type in the same region. This can be used to offset the fees for storage usage.
    • Renewal and upgrade

      You can renew and upgrade a storage plan. For more information, see Manage storage plans.

Examples

Example 1: Mr. Wang created a Capacity NAS file system in the China (Hangzhou) region. The average storage usage per hour in January 2021 is 90 GiB. The following table lists the monthly fees that were incurred by the file system based on resource plans and the pay-as-you-go billing method.
Billing method Fee
Pay-as-you-go Storage usage fee = 90 GiB × 0.06 USD/GiB/month = USD 5.4.
Resource plan for General-purpose NAS file systems (100 GiB, one month). Storage usage fee = USD 4.57

A resource plan (100 GiB, one month) for a General-purpose NAS file system in the China (Hangzhou) region costs USD 4.57.

Example 2: Mr. Zhang created a Performance NAS file system and a Capacity NAS file system in the China (Hangzhou) region. The average storage usage per hour for the Performance NAS file system in January 2021 is 20 GiB. The following table lists the monthly fees that were incurred by the file systems based on resource plans and the pay-as-you-go billing method.
Billing method Fee
Pay-as-you-go Storage usage fee = 90 GiB × USD 0.06/GiB/month + 20 GiB × USD 0.3/GiB/month = USD 11.4
Resource plan for General-purpose NAS file systems (100 GiB, one month). The 100 GiB of storage capacity in the resource plan is used to offset 18.28 GiB of storage usage from the Performance NAS file system. The fees for the excess storage are calculated based on the pay-as-you-go billing method.

Storage usage fee = USD 4.57 + (20 - 18.28) GiB × USD 0.3/GiB/month + 90 GiB × USD 0.06/GiB/month = USD 10.486

A resource plan (100 GiB, one month) for a General-purpose NAS file system in the China (Hangzhou) region costs USD 4.57.

Resource plan for General-purpose NAS file systems (200 GiB, one month). Storage usage fee = USD 9.14

A resource plan (200 GiB, one month) for a General-purpose NAS file system in the China (Hangzhou) region costs USD 9.14.

FAQ