This topic describes the precautions and procedure for data migration.
- A migration job occupies the network resources of the source data address and destination data address. To ensure business continuity, we recommend that you specify a speed limit for a migration job or perform the migration job during off-peak hours.
- Before a migration job is performed, files at the source data address and the destination data address are checked. The files at the destination data address are overwritten if the source files have the same name as the destination files and have a later modification time. If two files have the same name but different content, you must change the name of one file or back up the files.
- If symbolic links exist at the source data address, the actual files to which the
symbolic links refer is migrated. The destination files have the same names as the
original symbolic links. For example, a symbolic link named a exists at Source Data Address A. The actual file that the symbolic link refers to
is b.jpg. During migration, b.jpg is migrated to the destination data address and renamed a. For more information about symbolic links, see Configure symbolic links.
Note If symbolic links exist during migration, the workloads of migration are more than estimated and the migration progress may exceed 100%. You can evaluate the actual progress based on the size of migrated files.
- Data Transport only allows you to migrate data of a single bucket at a time, rather than all data for an account.
Step 1: Create a source data address
- Log on to the Data Transport console.
- Choose Create Data Address., and click
- In the Create Data Address dialog box, configure the parameters and click OK.
Parameter Required Description Data Type Yes Select OSS. Data Region Yes Select a region where the source data address is located. For example, China (Zhangjiakou-Beijing Winter Olympics). Data Name Yes A data name must be 3 to 63 characters in length. Special characters are not supported, except for hyphens (-) and underscores (_). OSS Endpoint Yes Select an endpoint based on the region where your data is located.
Notice When creating a migration job, you can use an OSS bucket that is deployed in an internal network as the source data address. In this case, the destination data address can only be a network-attached storage (NAS) file system or OSS bucket that is deployed in the same region.
- You can use the following HTTP-based endpoint to access OSS from the Internet: http://oss-cn-endpoint.aliyuncs.com.
- You can also use the following HTTPS-based endpoint to access OSS from public networks: https://oss-cn-endpoint.aliyuncs.com.
- You can use an internal HTTP endpoint to access OSS from the internal network, for example, http://oss-cn-qingdao-internal.aliyuncs.com.
- You can use an internal HTTPS endpoint to access OSS from the internal network, for example, https://oss-cn-qingdao-internal.aliyuncs.com.
AccessKey Id and AccessKey Secret Yes Enter an AccessKey pair that is used to migrate data. For more information, see Create and grant permissions to a RAM user. OSS Bucket Yes Select the bucket that stores the data to be migrated. OSS Prefix Yes An OSS prefix cannot start with a forward slash (/) and must end with a forward slash (/). For example,
- You must apply for whitelist permissions because this feature is in the public preview phase. Click Application.
- Enter the required information and submit the application for using this feature. After the application is approved, you will receive a short message service (SMS) notification.
Step 2: Create a destination data address
The procedure used to create a source data address is the same as that used to create a destination data address. For more information about how to configure the required parameters, see Step 1.
Step 3: Create a migration job
- Choose Create Job., and click
- In the Create Job dialog box, read the Terms of Migration Service, select I understand the above terms and conditions, and apply for opening data migration
service, and then click Next.
Then, the Fee Reminder dialog box appears.
- In the Create Job dialog box, configure the parameters and click Next.
Parameter Required Description Job Name Yes A job name must be 3 to 63 characters in length and can contain lowercase letters, digits, and hyphens (-). It cannot start or end with a hyphen (-). Source Data Address Yes Select the source data address that you have created. Destination Data Address Yes Select the destination data address that you have created.Notice If the source data address and the destination data address are located in different countries or regions, you must submit a ticket to request permissions to create a cross-country or cross-region migration job. You must ensure that your business is legitimate, data transit conforms to local rules and regulations, and data does not include illegal information. Specified Directory No
- Do not filter: All data at the source data address is migrated.
- Exclude: The files and subdirectories in the excluded directories are not migrated.
- Contain: Only the files and subdirectories in the specified directories are migrated.
- A directory cannot start with a forward slash (/) or a backslash (\), and cannot contain double slashes (//), double periods (..), or double quotation marks ("). The character string that consists of all the specified directory names cannot exceed 10 KB in size.
- A directory must end with a forward slash (/), for example, docs/.
- You can specify a maximum of 20 directories of the Exclude or Contain type.
Migration Type Yes
Notice Before you start a migration job, Data Transport compares files of the source data address with those of the destination data address. If a source file has the same name as a destination file, the destination file is overwritten when one of the following conditions is met:
- Full: specifies a full migration job. You must specify the Start Time Point of File parameter. Files with the last modification time later than the specified start time point are migrated. After the files are migrated, the migration job is closed. You can submit the job again if the data at the source data address changes. In this case, Data Transport only migrates the data that is changed after the previous job.
- Incremental: specifies an incremental migration job. To perform an incremental job, specify the Migration Interval and Migration Times parameters based on your needs. You must specify the Start Point Time of File parameter. Files with the last modification time later than the specified start time point are migrated during the first migration. After the first migration is complete, an incremental migration is performed based on the migration interval. An incremental migration job only migrates files that are created or modified after the previous migration started and before this migration starts. Assume that you specify N for the migration times. Full migration is performed once. Then, incremental migration is performed (N-1) times. For example, you can set the migration interval to 1, the migration times to 5, and the start time point to 2019-03-05 08:00. The present time is 2019-03-10 08:00. When the first migration starts, Data Transport migrates files that are last modified between 2019-03-05 08:00 and 2019-03-10 08:00. Assume that the first migration requires 1 hour to complete. The second migration starts at 2019-03-10 10:00. The two hours from 8:00 to 10:00 include the time period that the first migration requires (1 hour) and the migration interval (1 hour). During the second migration, files that are last modified between 2019-03-10 08:00 and 2019-03-10 10:00 are migrated. The migration job includes a full migration and four incremental migrations.
- The content types of the source file and the destination file are different.
- The source file is updated after the previous migration.
- The size of the source file is different from that of the destination file.
Start Time Point of File Yes
- All: All files are migrated.
- Assign: Files that are created or modified after the specified time are migrated. For example, if you set the start time point to 2018-11-01 08:00:00, only files that are created or modified after 2018-11-01 08:00:00 are migrated. Files that are created or modified before the specified time are skipped.
Migration Interval Yes (only for incremental migration) The default value is 1 hour and the maximum value is 24 hours. Migration Times Yes (only for incremental migration) The default value is 1 and the maximum value is 30.
- On the Performance tab, navigate to the Data Prediction section and specify the Data Size and File Count parameters.
- Optional. On the Performance tab, navigate to the Flow Control section, specify the Time Range and Max Flow parameters, and then click Add.
Note To ensure business continuity, we recommend that you specify the Time Range and Max Flow parameters based on the fluctuation of workloads.
- Click Create and wait until the migration job is completed.