This topic describes how to prepare for a migration job.

Estimate the amount of data to be migrated

Estimate the size and number of files that you want to migrate. Log on to the Object Storage Service (OSS) console. On the Buckets tab, click the name of a bucket in which the data that you want to migrate is stored. Then, click the Overview tab to view the bucket size and the number of files in the bucket.
Note To ensure a successful migration, you must specify valid values for the size and number of files when you create a migration job.

Restore data in the source bucket

Data Online Migration does not restore data in archived files during migration. Before you create a migration job to migrate data of the Archive storage class, you must manually restore the data. Otherwise, the files that are not restored or are being restored cannot be migrated. For more information about how to restore data of the Archive storage class, see Solutions to migrate archived data.
Note
  • Before you create a source data address and a migration job, make sure that data of the Archive storage class is restored.
  • The time required to restore data of the Archive storage class is based on the amount of data. Make sure that you specify an appropriate value for the restoration duration. This can prevent data from entering the archived state during migration.
  • You may be charged for the restoration operation. For information about the billing methods, contact the service provider that offers the source bucket.

Create a destination bucket

Create a destination OSS bucket to store the migrated data. For more information, see Create buckets.

Create and authorize a RAM user

Note If you need to migrate data across accounts, you must create RAM users for the Alibaba Cloud account to which the source bucket belongs and the Alibaba Cloud account to which the destination bucket belongs. Then, you must grant the required permissions to both RAM users.
  1. Log on to the Resource Access Management (RAM) console.
  2. In the left-side navigation pane, choose Identities > Users.
  3. On the Users page, click Create User.
  4. In the User Account Information section of the Create User page, configure the Logon Name and Display Name parameters.
  5. In the Access Mode section, select Console Access and Open API Access. Then, save the generated logon name, password, AccessKey ID, and AccessKey secret.
    • Console Access: If you select this option, you must configure the Console Password, Password Reset, and Multi-factor Authentication parameters.
    • Open API Access: If you select this option, an AccessKey pair is automatically created for the RAM user. The RAM user can call API operations or use other development tools to access Alibaba Cloud resources.
    Note If you need to migrate data across accounts, you must save the logon name, password, AccessKey ID, and AccessKey secret that are generated for each RAM user by the corresponding Alibaba Cloud account.
  6. After the RAM user is created, return to the Users page. Find the RAM user and click Add Permissions in the Actions column. In the panel that appears, select the AliyunOSSFullAccess and AliyunMGWFullAccess policies and click OK. This way, the RAM user is granted the permissions to read and write files from OSS and perform online data migrations.
  7. In the left-side navigation pane, click Overview.
  8. On the page that appears, navigate to the Account Management section and click the link under RAM user logon. On the page that appears, enter the logon name and password of the RAM user to log on to the Alibaba Cloud Management Console.