Billing of IA storage media - Billing| Alibaba Cloud Documentation Center

Limits

Infrequently accessed files are dumped from a file system to an IA storage medium only in batches to ensure the performance of the file system. Dumped files no longer occupy the storage space of the file system. When the files are being dumped, each file has a replica in the storage space of the file system and the IA storage medium. This temporarily increases storage usage and generates additional fees. After the files are dumped, the replica and files in the file system are deleted and no longer generate additional fees.

Billable items

Note IA storage media cannot be separately purchased. For more information, see IA storage media.


Billable item	Description
Storage usage	The usage of a General-purpose NAS file system and the usage of an IA storage medium. Fees are calculated based on the maximum used storage per hour. The used storage space indicates 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 size of the file is counted as 4 KiB. If the size of a file is 6KiB, the size of the file is counted as 8 KiB. File holes occupy storage space in NAS. 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 type during the retention period. For example, if 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. Likewise, if 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 the recycle bin feature.
Read and write traffic	Traffic fees are generated when the data in an IA storage medium is accessed. Fees are calculated based on the total amount of read and write traffic per hour. The amount of read and write traffic is reset to 0 each time an hourly bill is generated. The amount of read and write traffic starts from 0 again for the next hour. If the data in the file system meets the lifecycle management rules, the data is automatically dumped to the IA storage medium. No write traffic fees are generated for the data transfer. If you access files in an IA storage medium, you are charged for the actual read and write traffic that is generated. If you read only a part of a file, you are charged for the read traffic that is generated. If you run a data retrieval task, you are charged for read traffic based on the size of the retrieved files. If you back up files from an IA storage medium, you are charged for read traffic based on the size of the files. If you use security services such as the anti-ransomware service of Security Center to scan files in an IA storage medium, you are charged for the actual read and write traffic that is generated. You are not charged for managing metadata in the IA storage medium. For example, you are not charged for running the ls command to show the metadata of specified files.

Billing cycle

The fees that are generated within an hour are deducted from your account balance in the next hour. For example, you are billed at 09:30:00 for the fees that are generated from 08:00:00 to 09:00:00 of the same day.

Note The bill that you receive at 09:30:00 may include only the fees that are generated from 07:00:00 to 08:00:00 because of system latency.

Comparison of billing methods

By default, NAS file systems are billed based on the pay-as-you-go billing method. You can also 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 (-) indicates that the operation is not applicable to the billing method.

Note If you have resource plans, SCUs, and storage plans within your Alibaba Cloud account, storage usage fees are offset based on the following sequence: storage plans, resource plans, and SCUs. Then, you are charged based on the pay-as-you-go billing method.


Type	Billable item	Purchase	Offset the storage usage fees of General-purpose NAS file systems of different storage types	Offset the storage usage fees of multiple NAS file systems	Offset only the storage usage fees of NAS file systems	Renewal	Upgrade	Purchase multiple resource plans
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	✓	✓	✓	✓	✓	✓	✓
Storage plan	Storage usage of General-purpose NAS file systems Storage usage of IA storage media	×	×	×	✓	✓	✓	×
Storage capacity units (SCUs)	Storage usage of General-purpose NAS file systems	✓	✓	✓	×	×	×	✓

Billing methods

Pay-as-you-go
After you create a NAS file system, you are billed based on the pay-as-you-go billing method by default.
The storage usage fee in a billing cycle is calculated by using the following formula: Storage usage fee = Storage usage fee of a General-purpose NAS file system + Storage usage fee of an IA storage medium + Traffic fee of the IA storage medium = Maximum storage usage of a General-purpose NAS file system per hour × Unit price per hour + Maximum storage usage of an IA storage medium per hour × Unit price per hour + Amount of read traffic × Unit price per hour + Amount of write traffic × Unit price per hour
Note
- If the lifecycle management feature is enabled, the storage usage of the General-purpose NAS file system is a storage space. This storage space is occupied by the data that is not dumped to an IA storage medium.
- 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. In some cases, the storage usage that is displayed in the console at the current local time is the storage usage in the previous hour because of latency.
- General-purpose NAS file systems are divided into two types: Capacity NAS file system and Performance NAS file system. The two types have different unit prices for storage usage. For NAS file systems, the unit of storage usage fee is USD/GiB/month.When you calculate the storage usage fee, you must convert the unit of measurement to USD/GiB/hour. For more information, see Apsara File Storage NAS pricing.

Resource plans (recommended)

A resource plan is a type of subscription billing method. You can purchase multiple resource plans and use the resource plans to offset the storage usage fees of multiple file systems. Resource plans are applied to offset the fees based on the following sequence: Performance NAS file systems, Capacity NAS file systems, and IA storage media.

Purchase method
For more information about how to purchase a resource plan, see Manage resource plans.

Offset rules

The following table describes the rules that are applied when you use resource plans to offset the storage usage fees of different storage types of NAS file systems in the Chinese mainland. To view the relevant information about the offset rules that are applied in other regions, you can use the calculator.


Specification	Conversion coefficient	Description
Capacity NAS file system	1	You can use 1 GiB of base capacity in your General-purpose NAS resource plan to offset the fee for 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 NAS resource plan to offset the fee for 1 GiB of storage usage from a Performance NAS file system.
IA storage media	0.37	You can use 0.37 GiB of base capacity in your General-purpose resource plan to offset the fee for 1 GiB of storage usage from an IA storage medium.

You can use the calculator that is provided by Alibaba Cloud to calculate the fees that are offset by 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.

Storage capacity units (SCUs)

An SCU is a type of subscription billing method. You can purchase multiple SCUs 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.

Offset rules

You can use SCUs to offset the storage usage fees of NAS, Object Storage Service (OSS), and Elastic Compute Service (ECS) resources. The following table describes the rules that are applied when you use SCUs to offset the storage usage fees of different storage classes of NAS file system in the Chinese mainland. For more information about the rules that are applied in other Alibaba Cloud storage services and regions, visit the Pricing page.


File system type	Offset factor	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	0.889	You can use 0.889 GiB of capacity in your SCU to offset the fee for 1 GiB of storage usage from a Performance NAS file system.

Examples

Mr. Chen purchased a General-purpose NAS resource plan of 500 GiB and an SCU of 40 GiB in the China (Beijing) region in January 2021. In February 2021 in the China (Beijing) region, the storage usage of the Capacity NAS file system is 600 GiB and the storage usage of the Performance NAS file system is 200 GiB. The following table shows the values that are obtained after NAS calculates the monthly usage fee of the file systems based on the resource plan and the SCU.


File system type	Offset by resource plans	Offset by SCUs
Capacity NAS file system	You can use 500 GiB of capacity in your resource plan to offset the fee for 500 GiB of storage usage from the Capacity NAS file system.	You can use 25 GiB of capacity in your SCU to offset the fee for 100 GiB of storage usage from the Capacity NAS file system.
Performance NAS file system	None	You can use 15 GiB of capacity in your SCU to offset 16.87 GiB of storage usage from the 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.
- Usage notes
  - A storage plan is used to first offset the storage usage fee of General-purpose NAS file systems. If the storage plan still has a positive balance, the storage plan is used to offset the storage usage fee of an IA storage medium based on a specific coefficient.
    - If the following condition is met, the storage plan is sufficient to offset the storage usage fee of the IA storage medium: (Capacity of the storage plan - Storage usage of the General-purpose NAS file system) × Coefficient - Storage usage of the IA storage medium ≥ 0 GiB.
    - If the following condition is met, the storage plan is insufficient to offset the storage usage fee of the IA storage medium: (Capacity of the storage plan - Storage usage of the General-purpose NAS file system) × Coefficient - Storage usage of the IA storage medium < 0 GiB. The fees for the excess storage usage are calculated based on the pay-as-you-go billing method.
      The coefficient in the preceding formulas varies based on the type of the file system. For Performance NAS file systems, the coefficient is 12.333. For Capacity NAS file systems, the coefficient is 2.333.
  - You can attach only one storage plan to a General-purpose NAS file system. When you delete the General-purpose NAS file system, the storage plan is automatically detached. You can attach the detached storage plan to another file system of the same type in the same region to offset storage usage fees.
- Renewal and upgrade
  You can renew and upgrade a storage plan. For more information, see Manage storage plans.

Billing examples

Example 1: Mr. Zhang has created a Performance NAS file system named File System A in the China (Beijing) region. The storage usage of File System A in January 2021 is 100 GiB per hour. In the storage usage, 10 GiB of data is stored in a General-purpose NAS file system, and 90 GiB of data is stored in an IA storage medium. The read traffic of the IA storage medium is 1 GiB and the write traffic of the IA storage medium is 2 GiB within the month. The following table lists the fees that are generated for File System A within the month based on storage plans and the pay-as-you-go billing method.


Billing method	Billing
Pay-as-you-go	Storage usage fee of General-purpose NAS file system = 10 GiB × USD 0.3/GiB/month = USD 3 Storage usage fee of the IA storage medium = 90 GiB × USD 0.02322/GiB/month = USD 2.0898 Read and write traffic fees of the IA storage medium Read traffic fee = 1 GiB × USD 0.00929/GiB = USD 0.00929 Write traffic fee = 2 GiB × USD 0.00929/GiB = USD 0.01858 Total fee = USD 3 + USD 2.0898 + USD 0.00929 + USD 0.01858 = USD 5.11767
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 first offset 10 GiB of storage usage from the Performance NAS file system. The remaining storage capacity of the resource plan is calculated by using the following equation: 100 GiB - 10 GiB × 5.47 = 45.3 GiB. The 45.3 GB of storage capacity is then used to offset 90 GiB of storage usage from the IA storage medium. The remaining storage capacity of the resource plan is calculated by using the following equation: 45.3 GiB - 90 GiB × 0.37 =12 GiB. Only the pay-as-you-go billing method can be used to calculate the read and write traffic fees of IA storage media. Read traffic fee = 1 GiB × USD 0.00929/GiB = USD 0.00929 Write traffic fee = 2 GiB × USD 0.00929/GiB = USD 0.01858 Total fee = USD 4.57 + USD 0.00929 + USD 0.01858 = USD 4.59787 USD 4.57 is the fee of a resource plan (100 GiB, one month) for a General-purpose NAS file system in the China (Beijing) region.

Example 2: Mr. Zhang has created a Performance NAS file system named File System A in the China (Beijing) region. The lifecycle management feature is enabled for the file system. The storage usage of File System A in January 2021 is 210 GiB per hour. In the storage usage, 10 GiB of data is stored in a General-purpose NAS file system and 200 GiB of data is stored in an IA storage medium. The read traffic of the IA storage medium is 1 GiB, and the write traffic of the IA storage medium is 2 GiB within the month. Mr. Zhang also has a Capacity NAS file system named File System B. The storage usage of File System B in January 2021 is 90 GiB per hour. The following table lists the fees that are generated for File System A within the month based on storage plans and the pay-as-you-go billing method.


Billing method	Billing
Pay-as-you-go	Storage usage fees of the General-purpose NAS file systems Storage usage fee of the Performance NAS file system = 10 GiB × USD 0.3/GiB/month = USD 3 Storage usage fee of the Capacity NAS file system = 90 GiB × USD 0.06/GiB/month = USD 5.4. Storage usage fee of the IA storage medium = 200 GiB × USD 0.02322/GiB/month = USD 4.644 Read and write traffic fees of the IA storage medium Read traffic fee = 1 GiB × USD 0.00929/GiB = USD 0.00929 Write traffic fee = 2 GiB × USD 0.00929/GiB = USD 0.01858 Total fee = USD 3 + USD 5.4 + USD 4.644 + USD 0.00929 + USD 0.01858 = USD 13.07187
Two resource plans for General-purpose NAS file systems (100 GiB, one month)	The 100 GiB of storage capacity in the resource plans is used to first offset 10 GiB of storage usage from the Performance NAS file system. The remaining storage capacity of the resource plan is calculated by using the following equation: 200 GiB - 10 GiB × 5.47 = 145.3 GiB. The 145.3 GiB of storage capacity is then used to offset 90 GiB of storage usage from the IA storage medium. The remaining storage capacity of the resource plan is calculated by using the following formula: 145.3 GiB - 90 GiB × 1 = 55.3 GiB. The 55.3 GiB of storage capacity is then used to offset 149.5 GiB of storage usage from the IA storage medium (55.3 GiB/0.37 ≈ 149.5 GiB). The excess storage usage of the IA storage medium is 50.5 GiB (200 GiB - 149.5 GiB = 50.5 GiB) is calculated based on the pay-as-you-go billing method by using the following formula: 50.5 GiB × USD 0.02322 = USD 1.17261. Only the pay-as-you-go billing method can be used to calculate the read and write traffic fees of IA storage media. Read traffic fee = 1 GiB × USD 0.00929/GiB = USD 0.00929 Write traffic fee = 2 GiB × USD 0.00929/GiB = USD 0.01858 Total fee = USD 4.57 × 2 + USD 1.17261 + USD 0.00929 + USD 0.01858 = USD 10.34048 USD 4.57 is the fee of a resource plan (100 GiB, one month) for a General-purpose NAS file system in the China (Beijing) region.

Example 3: Mr. Zhang has created a Capacity NAS file system named File System A in the China (Beijing) region. The storage usage of File System A in January 2021 is 1000 GiB per hour. In the storage usage, 200 GiB of data is stored in a General-purpose NAS file system, and 800 GiB of data is stored in an IA storage medium. The read traffic of the IA storage medium is 1 GiB and the write traffic of the IA storage medium is 2 GiB within the month. The following table lists the fees that are generated for File System A within the month based on storage plans and the pay-as-you-go billing method.


Billing method	Billing
Pay-as-you-go	Storage usage fee of the General-purpose NAS file system: 200 GiB × USD 0.06/GiB/month = USD 12 Storage usage fee of the IA storage medium = 800 GiB × USD 0.02322/GiB/month = USD 18.576 Read and write traffic fees of the IA storage medium Read traffic fee = 1 GiB × USD 0.00929/GiB = USD 0.00929 Write traffic fee = 2 GiB × USD 0.00929/GiB = USD 0.01858 Total fee = USD 12 + USD 18.576 + USD 0.00929 + USD 0.01858 = USD 30.60387
Storage plan (500 GiB, one month)	The 500 GiB of storage capacity in the resource plan is used to first offset 200 GiB of storage usage from the Capacity NAS file system. The remaining capacity of the resource plan is calculated by using the following formula: 500 GiB - 200 GiB = 300 GiB. Then, the 300 GiB of storage capacity is used to offset 699.9 GiB of storage usage from the IA storage medium (300 GiB × 2.333 = 699.9 GiB). The excess storage usage of the IA storage medium is 100.1 GiB (800 GiB - 699.9 GiB = 100.1 GiB). The fee for this storage usage is calculated based on the pay-as-you-go billing method by using the following formula: 100.1 GiB × USD 0.02322 = USD 2.324322. Only the pay-as-you-go billing method can be used to calculate the read and write traffic fees of IA storage media. Read traffic fee = 1 GiB × USD 0.00929/GiB = USD 0.00929 Write traffic fee = 2 GiB × USD 0.00929/GiB = USD 0.01858 Storage usage fee = USD 22.85 + USD 2.324322 + USD 0.00929 + USD 0.01858 = USD 25.202192 USD 22.85 is the fee of a storage plan (500 GiB, one month) for a Capacity NAS file system in the China (Beijing) region.