Creating a Batch Object Storage Migration Workflow

Notes and Constraints

• For more information, see What Are the Restrictions on Using MgC for Storage Migration?
• Data in the Deep Cold Archive storage of Alibaba Cloud OSS cannot be restored using the restoration function of MgC. You need to manually restore the data before migration.

Warnings

When you create a workflow, there are three options for Overwrite Existing: Never, Always, and If older or different size. If you choose Never, restarting the migration task after interruptions or pauses may cause incomplete data migration, but the task may still be displayed as successful, which affects data integrity. Use the Never option with caution.

Prerequisites

You have created a batch object storage migration plan.

Procedure

1. Sign in to the MgC console. In the navigation pane, under Project, select an application migration project from the drop-down list.
2. In the navigation pane, choose Migrate > Workflows.
3. Click Create Workflow in the upper right corner of the page.
4. In the Batch Object Storage Migration card, click Preview Steps to view the stages and steps predefined in the template and the detailed description of each stage and step. Steps of the Automated type will be automatically performed by MgC. Click Configure Workflow in the lower right corner.
5. In the Basic Information area, enter a name and description for the workflow.
6. In the Migration Plan area, select the created migration plan. Then you should view the overview of the migration plan. Click View Details to view more information about the plan.

   

7. In the Migration Cluster area, select the cluster used for the migration. The cluster selected in the migration plan is used by default, but you can select another one if needed. The modification is applied to the current workflow but not to the migration plan.
8. Configure the migration task based on Table 1.

   Table 1 Parameters for configuring a migration task

   Parameter	Value	Description
   Concurrent Subtasks	-	Set the maximum number of concurrent subtasks. There cannot be more than 10 concurrent subtasks for each online migration node. For example, if there are 2 online migration nodes, the maximum number of subtasks can be 20 or any number below.
   Overwrite Existing	Never	Files existing at the migration target are never overwritten. WARNING: If you choose Never for the initial migration, the attributes of involved parent folders at the source will not be migrated to the target. As a result, the folder attributes may be incomplete at the target. To avoid this issue, use the Never option with caution for the initial migration. If a migration task is paused or interrupted and then restarted or resumed, the Never option will cause the system to skip files that were not completely migrated earlier, but the task may still be marked as successful. This affects data integrity. To avoid this issue, use the Never option with caution.
   	Always	Files existing at the migration target are always overwritten.
   	If older or different size	Files that already exist at the target will be overwritten if they are older than or have different sizes from the paired files at the source. Verification will be performed for folders after their contents are migrated. Folders that already exist at the target will be overwritten if they have different last modification times, sizes, or permissions from the paired folders at the source. NOTE: The same overwriting policy is applied to empty folders as files.
   	If different CRC 64 checksum	If a source object has a CRC64 checksum different from the paired target object, the source object will overwrite the target one. Otherwise, the source object will be skipped during the migration. If either of them does not have a CRC64 checksum, their sizes and last modification times are checked. NOTE: This option is only available for migration on Huawei Cloud or from Alibaba Cloud or Tencent Cloud. Using this option requires that the target OBS bucket be added to the CRC64 feature whitelist.
   Consistency Check	Size and last modified	With this default method, the system checks data consistency by comparing object size and last modification time.
   	CRC64 checksum	The system verifies data consistency by comparing CRC64 values in the metadata. If a source object and the paired destination object have CRC64 checksums, the checksums are checked. Otherwise, their sizes and last modification times are checked. NOTE: This option is only available for migration on Huawei Cloud or from Alibaba Cloud or Tencent Cloud. Using this option requires that the target OBS bucket be added to the CRC64 feature whitelist.
   Migrate Metadata	-	Decide whether to migrate metadata. If you select this option, object metadata will be migrated. If you do not select this option, only the Content-Type and Content-Encoding metadata will be migrated.

9. (Optional) Configure advanced options based on Table 2.

   Table 2 Advanced options

   Parameter	Description
   Record Migration Results	Determine the migration results you want to record. After the migration is complete, records are automatically generated and saved to the /oms directory in the target storage systems. Multiple options can be selected. For example, if you select Migrated objects, all migrated objects will be recorded in a file, and the file will be saved to the /oms directory in the target storage systems.
   Migrate Incremental Data	If you select No, incremental migration will not be performed.
   	If you select Yes, configure the overwriting policy and the execution mode for incremental migration. For details, see Configuring Incremental Migration Settings.
   Target Storage Class	Choose the storage class that your data will be migrated to in the target bucket. For details about storage classes, see Introduction to Storage Classes.
   Enable KMS Encryption	If you do not select this option, whether migrated data will be encrypted in the target bucket depends on the server-side encryption setting of the bucket. If you select this option, all migrated objects will be encrypted before they are stored in the target bucket. NOTE: Using KMS to encrypt migrated data may slow down the migration speed by about 10%. This option is only available when KMS is supported in the region you are migrating to.
   Restore Archive Data	If you do not select this option, the system records archive objects in the list of objects that failed to be migrated and continues to migrate other objects in the migration task. If you select this option, the system automatically restores and migrates archive objects in the migration task. If an archive object fails to be restored, the system skips it and records it in the list of objects that failed to be migrated and continues to migrate other objects in the migration task. NOTE: The system will restore archive data before migrating it, and you pay the source cloud platform for the API requests and storage space generated accordingly.
   Filter Source Data	Filter files to be migrated by applying filters. For details about the filters, see Source Data Filters.
   Download Data from CDN	If the default domain name cannot meet your migration requirements, then as long as the source cloud service provider supports custom domain names, you can bind a custom domain name to the source bucket, and enable the CDN service on the source platform to reduce data download expenses. Enter a custom domain name in the Domain Name text box and select a transmission protocol. HTTPS is more secure than HTTP and is recommended. If the migration source is the Alibaba Cloud OSS or Tencent Cloud COS, you also need to select an authentication type and enter an authentication key.
   Send SMN Notification	Determine whether to use SMN to get notifications about migration results. If you do not select this option, no SMN messages are sent after the migration. If you select this option, after the migration, SMN messages are sent to the subscribers of the selected topic. You can select the language and trigger conditions for sending messages.
   Limit Traffic	Allocate the maximum bandwidth to be used by the workflow during a specified period. If you do not select this option, migration traffic is not limited. If you select this option, limit the migration traffic by setting Start Time, End Time, and Bandwidth Limit. For example, if you set Start Time to 08:00, End Time to 12:00, and Bandwidth Limit to 20 MB/s, the maximum migration speed is limited to 20 MB/s when the migration task runs from 08:00 to 12:00. The migration speed is not limited beyond this period. NOTE: The rate limit ranges from 0 MB/s to 1,048,576 MB/s. A maximum of five rules can be added. The time is the local standard time of the region you are migrating to.

10. Click Next: Confirm.
11. Confirm the workflow settings and click Confirm. The Run Workflow dialog box is displayed, which indicates that the workflow has been created.
    • If you want to start the migration immediately, click Confirm to run the workflow.
    • If you want to add a stage or step to the workflow, click Cancel. The workflow enters a Waiting state, and the migration is not started. To start the migration, click Run in the Operation column.

12. On the migration workflow details page, view the workflow settings and the migration progress. You can also perform the following operations:
    • Move the cursor to the migration progress bar of a resource. In the displayed window, view the migration details about the resource.
    • When a migration reaches a step that requires manual confirmation, place the cursor on the progress bar and click Confirm next to the step status in the displayed window. The migration can continue only after you confirm.
    • In the Basic Information area, click Manage next to the cluster name. The cluster details page is displayed on the right. On the displayed page, you can:
      • Add, edit, or delete traffic limiting rules to control cluster traffic based on your requirements.
      • Add or delete migration nodes or list nodes, or upgrade plug-ins for existing nodes as required.
    • In the Basic Information area, expand Advanced Settings. Review the incremental migration settings. If Incremental Migration Method is set to Automated, you can modify the number of incremental migrations.

Configuring Incremental Migration Settings

The following table describes the parameters about incremental migration.

Table 3 Configuring incremental migration settings

Parameter	Description
Overwrite Existing During Incremental Migration	For details, see Table 1. NOTE: This setting only applies to incremental migration.
Incremental Migration Method	Manual: You can manually initiate an incremental migration after the first incremental migration defined in the workflow is complete. Automated: You can define the interval, maximum attempts, and time zone to trigger incremental migrations. For example, if you configure the incremental migration settings as shown in the following figure, the system will initiate incremental migration at 8:00 a.m. on Mondays, GMT+8, for the next two weeks.

• If you select Manual, incremental migration will be executed immediately when the workflow reaches the BatchCreateIncrementalMigrationTasks step.
• If you select Automated, when the workflow reaches the BatchCreateIncrementalMigrationTasks step, you can:
  • Manually perform incremental migration immediately when you are waiting for automatic incremental migration.
  • Skip incremental migration and verify services.