This topic answers frequently asked questions about lifecycle management in Apsara File Storage NAS.

Configurations

  • Why am I unable to configure lifecycle management policies for my file system?

    From June 1, 2020 to September 1, 2020, the lifecycle management feature is supported only for NAS file systems that are created after June 1, 2020.

    You will be able to configure lifecycle management policies for all NAS file systems since September 1, 2020.

  • How do I configure lifecycle management polices?

    Use the NAS console or OpenAPI Explorer to configure lifecycle management policies. For more information, see Manage lifecycle management policies and the following topics that describe API operations used for lifecycle management: CreateLifecyclePolicy, ModifyLifecyclePolicy, DeleteLifecyclePolicy, and DescribeLifecyclePolicies.

Scenarios and limits

  • When are files transitioned to the Infrequent Access (IA) storage class?
    A file is transitioned to the IA storage class if the file meets the following conditions:
    • A lifecycle management policy is configured for the directory where the file resides.
    • The size of the file is at least 64 KB.
    • The file is not accessed for the period of time that is configured in the lifecycle management policy.

    When you create lifecycle management policies, you can configure rules to transition the files that are not accessed for 14 days, 30 days, 60 days, or 90 days to the IA storage class. The lifecycle management feature determines whether a file is not accessed for a period of time based on the last access time (atime) of the file.

    The following operations update the atime of a file:
    • Read data from the file
    • Write data to the file
    The following operations do not update the atime of a file:
    • Rename the file
    • Modify the user, group, mode, or other attributes of the file
  • What happens if several lifecycle management policies are configured for a directory?

    Files in the directory are transitioned to the IA storage class if they meet the rule in any lifecycle management policy.

  • What happens if two different lifecycle management policies are configured for a directory and its subdirectory?

    Files in the subdirectory are transitioned to the IA storage class based on both of the two policies.

    For example, a policy whose atime threshold is 60 days is configured for a directory, and a policy whose atime threshold is 14 days is configured for a subdirectory. Files in the subdirectory that are not accessed for 14 days are transitioned to the IA storage class. Then, the files in the IA storage class are skipped when the lifecycle management feature checks for infrequently accessed files based on the policy of the parent directory.

  • How long does a lifecycle management policy require to take effect?

    A lifecycle management policy requires less than two hours to take effect. This means that the lifecycle management feature transitions the first file that meets the policy to the IA storage class within two hours after the policy is configured.

  • Is lifecycle management affected if a file or directory is renamed?

    If a directory for which a lifecycle management policy is configured is renamed, files in the directory are no longer subject to the lifecycle management policy. Files in the IA storage class remains in the IA storage class.

    If a lifecycle management policy is configured for the new path of a renamed file or directory, the file or files in the directory that meet the policy are transitioned to the IA storage class.

  • What happens if a lifecycle management policy is deleted?

    Files in the directory for which a policy is configured will no longer be transitioned to the IA storage class. Files in the IA storage class are not immediately transitioned to the Standard storage class.

  • Will files in a directory be repeatedly transitioned to the IA storage class if a policy is deleted and re-created for the directory?

    After you create the policy, the lifecycle management feature checks for infrequently access files. However, files in the IA storage class are skipped in the check. This prevents repeated file transition.

Performance

  • Are files in the IA storage class accessible?

    Yes, files in the IA storage class are accessible. You can perform read/write operations on files in the IA storage class in the same way as you perform read/write operations on other files in a file system.

  • Is access latency of a file in the IA storage class higher than other files in a NAS Performance and NAS Capacity file system?

    The read latency of a file in the IA storage class may be high. However, after a file is read from the IA storage class, the file is cached in the Standard storage class. Then, the read latency of the file is similar to that of other files in a NAS Performance and NAS Capacity file system.

    The write latency of a file in the IA storage class is similar to that of other files in a NAS Performance and NAS Capacity file system.

Billing

  • What are data transfer fees?

    Data transfer fees are incurred when files in the IA storage class are accessed. For more information about billing items and methods, see Billing of IA storage media.