Preparations - Data Online Migration - Alibaba Cloud Documentation Center

This topic describes the operations that you must perform before you migrate data.

Step 1: Estimate the amount of data that you want to migrate

Estimate the size and the number of files that you want to migrate. You can log on to the UPYUN Storage Service (USS) console to view the size and the number of files.

Note

To ensure a successful migration, you must specify appropriate values for the size and the number of files when you create a migration task.

Step 2: Create a destination bucket

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

Step 3: Create a RAM user that is used to migrate data

To ensure data security, we recommend that you create a RAM role and attach the required policies to the RAM role based on the principle of least privilege for data migration.

Log on to the RAM console.
In the left-side navigation pane, choose Identities > Roles.
On the Roles page, click Create Role.
In the Select Role Type step of the Create Role wizard, select Alibaba Cloud Service and click Next.
In the Selected Trusted Entity section, select Normal Service Role as Role Type, enter a RAM role name in the RAM Role Name field, and select Data Online Migration from the Select Trusted Service drop-down list. Then, click OK.

Step 4: Grant permissions to the RAM user

After the RAM user is created, go to the Users page in the RAM console. Find the RAM user that you want to manage and click Add Permissions in the Actions column to grant permissions to the RAM user.

System policy: AliyunMGWFullAccess, which grants full permissions on Data Transport
Custom policy:
Grant the RAM user full permissions on the destination bucket
Note
- The following policy is for reference only. Replace mybucket with the name of the destination bucket.
- For more information about RAM policies for OSS, see Common examples of RAM policies.
```
{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "oss:*",
            "Resource": [
                "acs:oss:*:*:mybucket",
                "acs:oss:*:*:mybucket/*"
            ]
        }
    ]
}
```