Migration with Back-to-Source

Advantages

This solution has the following advantages:

• Zero service interruptions: Your services are not interrupted during the whole migration process. This helps you deliver smooth user experience.
• High reliability: You can perform service verification before the service cutover starts and after the migration finishes.

Process

The following figure shows the migration process with OMS and OBS back-to-source.

Figure 1 Process of migrating data using OMS and OBS back-to-source

The following figure shows the migration procedure.

Figure 2 Migration diagram

The procedure is as follows:

1. T1: full migration and verification on Huawei Cloud

   (1) Migrate all data generated before the time point T1 from the source bucket to the destination bucket on Huawei Cloud. During this period, your service systems continue to write data to the source bucket.

   (2) Verify the migration is successful and the data migrated to Huawei Cloud can be downloaded and uploaded.

2. T2: incremental data migration and evaluation of data growth rate

   (3) Migrate the incremental data generated from T1 to T2 to Huawei Cloud.

   (4) Evaluate data growth rate to determine the time window for service verification.

3. T3: back-to-source configuration in OBS, service cutover, and incremental migration

   (5) Configure back-to-source for the destination OBS bucket and cut services over to Huawei Cloud at T3. Then incremental data generated before T3 in the source bucket can be accessed through back-to-source without interrupting your services, and new service data will be stored into the destination bucket, rather than the source bucket.

   (6) Migrate incremental data generated from T2 to T3 to Huawei Cloud.

   (7) Compare the total number and size of objects in the source and destination buckets to check that all data in the source bucket has been migrated.

OMS makes API calls to the object storage service on the source platform during the migration. These API calls may generate fees on the source platform, and you will be responsible for those fees based on those source platform billing structures.

Prerequisites

• You have registered a HUAWEI ID and enabled Huawei Cloud services.
• You have obtained the AK/SK pairs and required permissions for the source and destination platform accounts.
  • The source platform account needs the permissions for:
    • Listing buckets
    • Obtaining bucket locations
    • Listing objects
    • Obtaining object metadata
    • Obtaining object content

    For details about how to obtain these permissions, see Source Permissions.

  • The destination platform account needs the permissions for:
    • Listing buckets
    • Obtaining bucket locations
    • Listing objects
    • Obtaining object metadata
    • Obtaining object content
    • Listing uploaded parts
    • Restoring archive objects

    For details about how to obtain these permissions, see Destination Permissions.

• You have created at least one bucket on OBS.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select the desired region.
3. Click Service List. Under Migration, click Object Storage Migration Service.

   The Object Storage Migration Service page is displayed.

4. Create a migration task or migration task group to migrate the source data.
   • If there is more than 3 TB of data or more than 5 million objects to migrate, create a migration task group. For details, see Creating a Migration Task Group.
   • If there is not a lot of source data, create a migration task. For details, see Creating a Migration Task.

5. After the migration and verification is complete, go to OBS console, create back-to-source rules for the destination OBS bucket, and switch services to Huawei Cloud.

   For details, see .

6. Back to the OMS console, create a migration task or migration task group for the source bucket again. During this migration, OMS fully compares the objects in the source and destination buckets, synchronize all data that is not migrated or modified from the source bucket to the destination bucket. For detailed comparison rules, see How Does Migration Affect Data in the Destination Bucket?

   If there is more than 3 TB of data or more than 5 million objects to migrate, create a migration task group. For details, see Creating a Migration Task Group.

   If there is not a lot of source data, create a migration task. For details, see Creating a Migration Task.