Creating a Tiering Policy

Prerequisites

You have created a file system.

Precautions

For a directory, if it is created with a tiering policy, such policy is applied preferentially. If the directory is not created with a tiering policy, it inherits the policy created for its parent directory.

Procedure

1. Choose Services > HDFS Service > Tiering.
   

   By default, the tiering policy function is disabled by the storage system. When you go to the Tiering page for the first time, you need to click Enable to enable the tiering policy function. After the function is enabled, you can log in the CLI and run the change tier_global_parameter tier_switch=off command to disable it.

2. Click Create Policy.

   The Create Policy page is displayed.

3. Select Placement policy or Migration policy in Policy Type and set basic information about the policy.
   • Placement policy
     Table 1 describes related parameters.

     Table 1 Placement policy parameters

     Parameter	Description
     Name	Indicates the name of the placement policy. NOTE: The name must be unique. The name contains only letters, digits, hyphens (-), and underscores (_). The name contains 1 to 63 characters.
     File System	Indicates the file system for which the placement policy takes effect. Click Select. On the File System page that is displayed, select a desired file system and click OK.
     File Directory	Indicates the file directory for which the placement policy takes effect. That is, a file directory in a file system on the storage system. If this parameter is not specified, the placement policy takes effect for the entire file system.
     Tier Grade	Indicates the tier grade of the placement policy. That is, the tier grade of the disk pool to which data is written. A disk pool's tier grade is specified during disk pool creation.

   • Migration policy

     Select Migration policy in Policy Type.

     Table 2 describes related parameters.

     Table 2 Migration policy parameters

     Parameter	Description
     Name	Indicates the name of the migration policy. NOTE: The name must be unique. The name contains only letters, digits, hyphens (-), and underscores (_). The name contains 1 to 63 characters.
     File System	Indicates the file system for which the migration policy takes effect. Click Select. On the File System page that is displayed, select a desired file system and click OK.
     File Directory	Indicates the file directory for which the migration policy takes effect. If no file directory is specified, the migration policy takes effect for the entire file system.
     Filter Policy	Indicates a file filtering policy. Possible options are By file name and By file operation time. By file name Select Including or Excluding in File Name Filtering to determine whether files with the specified names are included or excluded in the migration policy. Then, specify the file names to be filtered for or filtered. NOTE: 1 to 1023 characters can be entered in the text box. Wildcard (*) can match any character. The following formats are supported: *, *example*, *example, example*, and example*example. Multiple file names are separated using commas (,). By file operation time Specify a specific operation time. Then, the migration policy takes effect on files whose history operation times meet all of the specified times, including crtime, mtime, ctime, and atime. crtime: indicates the file creation time. mtime: indicates the file modification time. ctime: indicates the file property modification time. atime: indicates the last file access time.
     Tier Grade	Indicates the tier grade of the migration policy. That is, the grade of the disk pool to which files are migrated. A disk pool's tier grade is specified during disk pool creation.
     Execution Mode	Indicates the execution mode of the migration policy. Possible options are Periodical or One-off. NOTE: If Execution Mode is set to Periodical, the execution period of the migration policy is 24 hours. If Execution Mode is set to One-off, the migration policy is executed immediately.

4. Click OK.