Creating a Migration Task Group

This section describes how to create a migration task group.

By default, if a task stays in waiting state for more than 30 days, OMS automatically puts the task into Failed state and clears the AK/SK pair used by the task. To prevent task failures caused by blocking, do not create tasks too frequently.
If an object is larger than 500 GB, migrating it takes a long time. You can submit a service ticket to whitelist the object for migration in segments.
During the migration, the system automatically creates a temporary folder named OMS in the target bucket. Do not perform any operations on this folder, including but not limited to modifying, deleting, or adding data in the folder. Otherwise, the migration will be interrupted or fail.

Scenarios

If there is more than 3 TB of data or more than 5 million objects to migrate in a source bucket, you can create a migration task group to migrate the source data quickly. The system will group the source objects into multiple sub-tasks for concurrent migrations.

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 AliyunOSSReadOnlyAccess permission.
- The destination platform account needs the permissions required to list buckets, obtain bucket locations, list objects, obtain object metadata, obtain object content, upload objects, list uploaded parts, and restore archive objects. For details about how to obtain these permissions, see Destination Permissions.
You have created at least one bucket on OBS.
You have created less than 1,000,000 migration tasks within the past 24 hours.
You have less than 1,000,000 migration tasks in Waiting state.

Procedure

Log in to the Huawei Cloud console.
Click in the upper left corner and select the region where the destination bucket is located from the drop-down list.

Figure 1 Selecting the region where the destination bucket is located
Click Service List in the upper left corner, and choose Migration > Object Storage Migration Service.

You can also enter OMS in the search box to quickly find OMS.
Figure 2 Choosing OMS
In the navigation pane on the left, choose Migration Task Groups.
On the Migration Task Groups page, click Create Migration Task in the upper right corner.

Figure 3 Creating a migration task group
Read the service disclaimer, select I have read and agree to the service disclaimer, and click OK. The Create Migration Task Group page is displayed.

Figure 4 Select Source/Destination

Set parameters in the Select Source area. For details, see Table 1.

**Table 1** Parameters for configuring a source bucket
Parameter	Configuration
Data Source	Select Alibaba Cloud.
Access Key ID	Enter the AK of the Alibaba Cloud account to which the source bucket belongs.
Secret Access Key	Enter the SK of the Alibaba Cloud account to which the source bucket belongs.
Specify Source Bucket	Disable Specify Source Bucket (This feature is disabled by default.) Click List Buckets next to Bucket. All buckets in the account will be listed. Select the bucket you want to migrate from the drop-down list. NOTE: If the source platform account does not have the permissions required to list buckets, you need to enable Specify Source Bucket.
Specify Source Bucket	Enable Specify Source Bucket. Select the region where the source bucket resides from the Region drop-down list. In the Bucket text box, enter the name of the bucket or the directory to be migrated. The directory must have the bucket name included. Click Connect.

Set parameters in the Select Destination area and click Next. For details, see Table 2.

**Table 2** Parameters for configuring a destination bucket
Parameter	Configuration
Access Key ID	Enter the AK for the Huawei Cloud account to which the destination bucket belongs.
Secret Access Key	Enter the SK for the Huawei Cloud account to which the destination bucket belongs. Click List Buckets.
Bucket	Select a destination OBS bucket for storing the migrated data.

Click Next. The Set Task Group Parameters page is displayed.

Figure 5 Set Task Group Parameters
Select a migration method.
- Object name prefix
  1. Enter the names or name prefixes of the objects to be migrated in the text box under Bucket. If no object names or name prefixes are specified, all objects in the source bucket will be migrated.
    Figure 6 Entering the names or name prefixes of objects to be migrated
    If the objects you want to migrate are stored in the root directory of the source bucket, add their prefixes directly. If these objects are stored in none-root directories, add their directories and prefixes in the format of Bucket name/Folder name/Prefix.
    
    If no object names or prefixes are specified, all objects in the source bucket will be migrated.
    
    The objects to be migrated are recorded in .txt files, and each migration task has a list file. The storage path of the files is oms/taskgroup/ in the destination bucket. These list files will be retained after the migration, and you can manually delete them.
  2. Click Add. The system will automatically list the matched objects. You can click to delete the objects that do not need to be migrated from the list.
- Object list folder
  1. In the Object List Bucket (Huawei Cloud) drop-down list, select the bucket where the list files are stored.
    
    The bucket used for storing the list files must be located in the same region as the destination bucket, or you cannot select the files.
  2. Click Select next to Object List Folder. In the displayed Object List File dialog box, select the folder where the list files are stored, and click OK.
    Figure 7 Selecting the folder where the object list files are located
    An object list file cannot exceed 1,024 MB.
    
    A maximum of 2,000 object list files can be stored in the object list folder.
    
    An object list file must be a .txt file, and the ContentType metadata of the file must be text/plain.
    
    An object list file must be in UTF-8 without BOM.
    
    Each line in an object list file can contain only one object name, and the object name must be URL encoded if it contains special characters or spaces.
    
    Spaces are not allowed in each line in an object list file. Spaces may cause migration failures because they may be mistakenly identified as object names.
    
    Each line in an object list file cannot be longer than 65,535 characters, or the migration will fail.
    
    The ContentEncoding metadata of each object list file must be left empty, or the migration will fail.
    
    Archived data can only be accessed and obtained by OMS after it is restored. If the object list files are archived, manually restore them before migration.
Determine whether to migrate metadata.
- If you select Do not migrate, OMS will only migrate the metadata ContentType.
- If you select Migrate, OMS will migrate supported metadata.
  
  Only Chinese characters, English characters, digits, and hyphens (-) can be migrated. Other characters cannot be migrated.
Set Selective Migration.
- If you do not need to filter source data by time, set this option to No.
- If you need to filter source data by time, set this option to Yes. Then only source data modified after the specified time will be migrated.

(Optional) Set Use Source Custom Domain Name based on Table 3.

**Table 3** Parameters
Parameter	Configuration
Use Source Custom Domain Name	This option is deselected by default. If the default domain name cannot meet your migration requirements, then if 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 fees. NOTE: If anti-leeching is used, you are advised to disable it or contact Huawei Cloud technical support. Select a transmission protocol for Transfer Protocol. NOTE: HTTPS is more secure than HTTP and is recommended. Enter a custom domain name of the bucket in the Custom Bucket Domain Name box.
Enable CDN Authentication	This option is deselected by default. If you use the CDN authentication provided by Alibaba Cloud, select this option and perform the following settings: Select Type C for Verification Type. Only Type C is supported for migration from Alibaba Cloud. Enter the CDN verification key in the Verification Key box. NOTE: The fees generated by using Alibaba Cloud CDN are billed by Alibaba Cloud. Before the migration, disable CDN optimization functions, such as Gzip compression, on the Alibaba Cloud CDN console, or the migration may fail. URL redirection is not supported.
Check	Click Check to check whether the configuration is correct. If the configuration fails the check, click Details to view the failure causes. If the configuration passes the check, complete other migration configurations.

Configure parameters in the Destination Configuration area.
1. Data Encryption If the destination bucket is a parallel file system (PFS), KMS encryption is not supported.
  - If KMS is not selected, all migrated objects will not be encrypted before they are stored into the destination bucket.
  - If KMS is selected, all migrated objects will be encrypted before they are stored into the destination bucket.
    Using KMS to encrypt migrated data may decrease the migration speed by about 10%.
    
    Data encryption is only available if KMS encryption is supported in the region you are migrating to.
2. Specify Prefix
  - If this option is set to No, the names of objects remain unchanged before and after the migration.
  - If this option is set to Yes, you can specify a prefix to rename or redefine the paths of objects migrated to the destination bucket.
    Figure 8 Specifying a prefix
    
    To learn how to use Specify Prefix, see Adding a Name Prefix or Path Prefix to Migrated Objects.
3. Object Storage Class
  Choose the storage class that your data will be migrated to. For details about storage classes, see Introduction to Storage Classes.

Click Advanced Settings. Set parameters in the Advanced Settings area based on Table 4.

**Table 4** Advanced settings
Parameter	Description
Failed Object Record	The default value is Yes. If this option is set to No, the system will not record the objects that fail to be migrated. If the migration fails and needs to be retried, all objects in the source bucket need to be migrated again. If this option is set to Yes, the system will record the objects that fail to be migrated. If the migration fails and needs to be retried, only failed objects need to be migrated again. NOTE: For a migration task, no matter it is contained in a task group or not, the objects that fail to be migrated are recorded in a list named after the task name, and the list is uploaded to the oms/failed_object_lists/ directory of the destination bucket. A maximum of 100,000 failed objects can be recorded in a failed object list file. If more than 100,000 objects fail to be migrated in a migration task, you are advised to rectify the fault based on the existing failed object list and perform the migration again.
Archive Data Restoration	The default value is No. If this option is set to No, the system directly records archive objects in the list of objects that failed to be migrated and continues to migrate other objects. If this option is set to Yes, the system automatically restores and migrates archive objects.
SMN Notification	Determine whether to use SMN to get notifications about migration results. The default value is No. If this option is set to No, no SMN message is sent after the migration. If this option is set to Yes, you will receive an SMN message informing you of the migration results.
Traffic Limiting	Set the maximum bandwidth for the migration task during a specified period of time. If you do not need to limit migration traffic, select No. If you need to limit migration traffic, select Yes.
Object Overwrite	Overwrite if source newer or different size: If a source object is not as large as or was last modified more recently than its paired destination object, the source object will overwrite the destination object. Otherwise, the source object will be skipped. Never overwrite: The system always skips source objects and keeps their paired destination objects. Overwrite if different CRC64 checksum: If a source object has a CRC64 checksum different from the paired destination object, the source object will overwrite the destination object. Otherwise, the source object will be skipped. 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. This option is applied only when the source object has the same encryption status as the destination one. Always overwrite: The system always allows source objects to overwrite their paired destination objects.
Consistency check	By size and last modification time: This is the default setting. The system checks object consistency with object size and last modification time. By CRC64 checksum: The system checks object consistency with CRC64 checksums. 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.
Priority	If there are a large number of tasks, you can set task priorities to determine the migration sequence.

Click Next to enter the confirmation page.
Confirm the source information, destination information, task group parameters, and advanced settings, and click Migrate Now. A message is displayed indicating that the task group has been submitted. The task group is displayed in the migration task group list.