This topic provides answers to some commonly asked questions about the advanced management features of Apsara File Storage NAS.

When can I enable the lifecycle management feature?

You can enable the lifecycle management feature to save costs when files in a General-purpose NAS file system are not frequently accessed. The files that meet the rule in the lifecycle management policy are then transitioned to the Infrequent Access (IA) storage medium. The files are stored at a lower cost and you can access the files at any time.

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

You cannot enable the lifecycle management feature or configure the lifecycle management policies because only General-purpose NAS file systems that are created after June 1, 2020 support this feature. In the Product Announcement section of the NAS console, you can view the updates of the lifecycle management feature.

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 CreateLifecyclePolicy.

When is a file transitioned to the IA storage medium?

A file is transitioned to the IA storage medium only 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 specified in the lifecycle management policy.
    When you create a lifecycle management policy, you can specify a rule to transition the files that are not accessed for 14 days, 30 days, 60 days, or 90 days to the IA storage medium. 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 multiple lifecycle management policies are configured for a directory?

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

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

Files in the subdirectory are transitioned to the IA storage medium 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 its subdirectory. Files in the subdirectory that are not accessed for 14 days are transitioned to the IA storage medium. Then, the files in the IA storage medium 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 (if exists) that meets the rule in the policy to the IA storage medium within 2 hours after the policy is configured.

How is the lifecycle management feature affected if a 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 medium remain in the IA storage medium.

If you configure a lifecycle management policy for the renamed directory, files in the directory that meet the rule in the policy are transitioned to the IA storage medium.

What happens if a lifecycle management policy is deleted?

Files in the directory for which the policy is configured will no longer be transitioned to the IA storage medium. Files in the IA storage medium remain in the IA storage medium.

Will files in a directory be repeatedly transitioned to the IA storage medium if a policy is deleted and reconfigured for the directory?

No, files will not be repeatedly transitioned to the IA storage medium. After you reconfigure the policy, the lifecycle management feature checks for files that meet the rule in the policy. However, files in the IA storage medium are skipped in the check. This prevents repeated file transition.

Are files in the IA storage medium accessible?

Yes, you can perform read/write operations on files in the IA storage medium 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 medium longer than other files in a NAS Performance and NAS Capacity file system?

Yes, the read latency of a file in the IA storage medium may be long. However, after the file in the IA storage medium is read, the file is cached in the NAS Performance or NAS Capacity file system. Then, the read latency of the file is similar to that of other files.

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

How am I charged when files are transitioned to the IA storage medium?

When files are transitioned to the IA storage medium, you are charged for the space usage of the IA storage medium and read/write traffic. For more information, see Billing of IA storage media.

Why is Resource Access Management (RAM) authorization required when I create a mount target in the classic network?

RAM authorization is required because the classic network does not support resource isolation at the network layer. To ensure the data security of your file systems, NAS allows only the ECS instances of your Alibaba Cloud account to access the file systems by using mount targets in the classic network. To enable NAS to query the ECS instances of your Alibaba Cloud account, you must use RAM to authorize NAS.
Note
  • After the authorization, NAS has only the permission to call the DescribeInstances operation. NAS uses the ECS instances only for authentication.
  • We recommend that you do not delete or modify the AliyunNASDefaultRole role in RAM. Otherwise, exceptions such as mount failure may occur.

How can I obtain an AccessKey pair?

You can create an AccessKey pair for an Alibaba Cloud account or a RAM user. When you call API operations, the AccessKey pair is required for authentication.

An AccessKey pair consists of an AccessKey ID and an AccessKey secret.
  • The AccessKey ID is used to identify a user.
  • The AccessKey secret is used to verify the identity of the user. You must keep the AccessKey secret strictly confidential.
Notice We recommend that you use the AccessKey pair of a RAM user to call API operations. This prevents against the leakage of the AccessKey pair of the Alibaba Cloud account. If the AccessKey pair of your Alibaba Cloud account is disclosed, all resources are under threat.
  1. Log on to the Alibaba Cloud Management Console with an Alibaba Cloud account.
  2. Move your pointer over the profile picture in the upper-right corner of the page and click AccessKey Management.
  3. In the Note dialog box, click Use Current AccessKey pair or Use AccessKey Pair of RAM User.
    Notice We recommend that you use the AccessKey pair of the RAM user to prevent against the leakage of the AccessKey pair of the Alibaba Cloud account.
    • Create an AccessKey pair for the Alibaba Cloud account.
      1. In the Note dialog box, click Use Current AccessKey Pair.
      2. On the AccessKey Management page, click Create AccessKey.
      3. In the Phone Verification dialog box, enter the verification code in the Verification Code field and click OK.
      4. In the Create AccessKey dialog box, you can view the AccessKey ID and AccessKey secret.

        You can click Save AccessKey Information to download the AccessKey pair.

    • Create an AccessKey pair for a RAM user
      1. In the Note dialog box, click Use AccessKey Pair of RAM User.
      2. On the Users page of the RAM console, click Create User.

        Skip this step if you want to create an AccessKey pair for an existing RAM user.

      3. In the left-side navigation pane, choose Identities > Users and find the RAM user.
      4. Click the logon name of the RAM user to go to the details page. In the User AccessKeys section of the Authentication tab, click Create AccessKey.
        Note
        • You can create a maximum of two AccessKey pairs for each RAM user.
        • After you create an AccessKey pair, you cannot view the AccessKey secret in the RAM console. We recommend that you keep the AccessKey secret strictly confidential.
      5. In the Phone Verification dialog box, enter the verification code in the Verification Code field and click OK.
      6. In the Create AccessKey dialog box, you can view the AccessKey ID and AccessKey secret.

        You can click Download CSV File or Copy to save the AccessKey pair.

Does NAS support the inotify subsystem?

No, NAS does not support the inotify subsystem. The combination of the inotifywait and rsync commands is commonly used for real-time file backup and synchronization. However, NAS file systems are incompatible with the inotify subsystem.

  • Working principle

    The inotifywait command is a user-mode interface of the Linux inotify subsystem that is implemented at the Virtual File System (VFS) layer. After you run the inotifywait command, changes to files are monitored at the VFS layer. If a file is created, deleted, or modified, the name of the file and the type of the operation are returned to the user-mode inotifywait process. Then, the inotifywait command returns the information to you.

  • Known issue
    The inotifywait process on a Network File System (NFS) client of an NFS file system cannot detect the operations that other clients perform on the file system. The following example describes the details:
    • A NAS file system is mounted on Client A and Client B, and the inotifywait process is started on Client A.
    • The inotifywait process can detect the operations that Client A performs on the files of the file system.
    • The inotifywait process cannot detect the operations that Client B performs on the files of the file system.
  • Workaround

    You can use the File Alteration Monitor (FAM) subsystem instead to monitor files and directories in a NAS file system. The FAM subsystem is implemented in user mode. An FAM daemon scans the directories in a file system on a regular basis to detect changes.

    However, the FAM subsystem has the following defects:
    • You must write code to call the FAM interface in your programs.
    • If a large number of files are being monitored, the performance of the FAM subsystem may be compromised. Many resources are consumed and real-time monitoring cannot be guaranteed.