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 Tencent Cloud Object Storage (COS) 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: Restore data in the source bucket

Before you create a migration task to migrate data of the Archive storage class, you must manually restore the data. Take note of the following items when you restore the data:

Before you create a source data address and a migration task, make sure that data of the Archive storage class is restored.
Specify the number of days during which the restored data remains in the restored state based on the amount of data that you want to migrate. This can prevent data from entering the archived state during data migration.
You may be charged for the restoration operation. The fee may be relatively high. For more information about the billing methods, contact the service provider that offers the source bucket.

Note

Data Online Migration does not restore data in archived files at the source data address during data migration. The files that are not restored or are being restored cannot be migrated.

For more information about how to restore archived objects in a Tencent Cloud Object Storage (COS) bucket, see Restoring Archived Objects.

Important

The information in the preceding link may be outdated due to changes in the original server and is for reference only.

Step 3: Create an AccessKey pair that is used to migrate data

Create an AccessKey pair for an account that has the read permissions on the source data. For more information, see AccessKey pair in the Tencent COS official documentation.

Important

The information in the preceding link may be outdated due to changes in the original server and is for reference only.

Step 4: 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 5: 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 6: 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/*"
            ]
        }
    ]
}
```