This topic describes the usage notes and procedure for data migration.
Usage notes
- Data Online Migration uses the standard and publicly available API operations provided by the storage service provider of the source data address to access the source data. The data accessed by Data Online Migration depends on the specific API operations that are implemented by the service provider.
- A migration job occupies the network resources of the source and destination data addresses. To ensure business continuity, we recommend that you specify a rate limit for your migration job or run your migration job during off-peak hours.
- Before a migration job starts, the system checks the files at the source data address and the destination data address. If the source and destination data addresses have files with the same name, and the last modification time of the source file is later than the last modification time of the destination file, the destination file is overwritten. If both files contain different information, we recommend that you change the name of one file or back up the destination file.
Step 1: Create a source data address
- Log on to the Alibaba Cloud Data Transport console.
- In the left-side navigation pane, choose Create Data Address. . On the page that appears, click
- In the Create Data Address panel, configure the parameters and click OK. The following table describes the parameters.
Parameter Required Description Data Type Yes Select NAS. Data Name Yes Enter a name. The name must be 3 to 63 characters in length. The name cannot contain special characters, except for hyphens (-) and underscores (_). Data Region Yes Select the region where the Elastic Compute Service (ECS) instance resides. NAS Type Yes Select Others. VPC Yes Select the virtual private cloud (VPC) where the ECS instance resides. Switches Yes Select the vSwitch to which the ECS instance is connected. NAS Address Yes Enter the private IP address of the ECS instance. Connection Method Yes Select a protocol type for the shared folder. Sub Folder Yes Enter the path of the shared folder that stores the data that you want to migrate. Connection Password No Specify whether a password is required to access the shared folder. - No Password: No username and password are required to access the shared folder.
- Use Password: A username and password are required to access the shared folder. You must enter a valid username and password.
Note If you use a Windows instance, you must enter a username and a password. If you use a Linux instance, this parameter is optional.Note For more information about the status of a new data address, see Data address status.
Step 2: Create a destination data address
- In the left-side navigation pane, choose Create Data Address. . On the page that appears, click
- In the Create Data Address panel, configure the parameters and click OK. The following table describes the parameters.
Parameter Required Description Data types Yes Select OSS. Data Name Yes Enter a name. The name must be 3 to 63 characters in length. The name cannot contain special characters, except for hyphens (-) and underscores (_). Data Region Yes Select the region where the destination data address resides. Enable Transfer Acceleration No Before Data Online Migration uses the transfer acceleration feature provided by Object Storage Service (OSS), enable the transfer acceleration feature for OSS buckets. The transfer acceleration feature takes effect within 30 minutes after it is enabled. After you enable the feature, wait for 30 minutes before you create a migration job. Important If you use the transfer acceleration feature to access your OSS buckets, you are charged additional transfer acceleration fees. For more information, see Enable transfer acceleration.OSS Endpoint Yes Select an endpoint based on the region in which your data is stored. For more information, see Regions and endpoints. AccessKey Id Yes Specify the AccessKey pair that is used to migrate data. For more information, see Create a RAM user and grant required permissions to the RAM user. AccessKey Secret Yes OSS Bucket Yes Select the bucket in which the data that you want to migrate is stored. OSS Prefix No An OSS prefix cannot start with a forward slash (/). An OSS prefix must end with a forward slash (/). For example, you can specify data/to/oss/
as the OSS prefix. If you want to migrate data to the root directory of the specified bucket, do not configure this parameter.
Step 3: Create a migration job
- In the left-side navigation pane, choose Create Job. . On the page that appears, click
- In the Create Job panel, read the terms of the migration service and select I agree to the above terms and activate the Data Transport service. Then, click Next.
- In the Fee Reminder message, click Yes, Go Ahead.
- In the Job Config step, configure the parameters and click Next. The following table describes the parameters.
Parameter Required Description Job Name Yes Enter a job name. The name must be 3 to 63 characters in length and can contain only lowercase letters, digits, and hyphens (-). It cannot start or end with a hyphen (-). Source Data Address Yes Select the source data address that you created. Destination Data Address Yes Select the destination data address that you created. Specified Directory No Specify the directories in which the files and subdirectories are migrated or not migrated. Valid values: - Do not filter: migrates all data from the source data address.
- Exclude: does not migrate the files or subdirectories in the specified directories.
For example, you want to migrate all the directories in the
root_dir/
directory exceptroot_dir/bad_sub1/
androot_dir/bad_sub2/
. In this case, you can select this method and specifybad_sub1/
andbad_sub2/
. - Contain: migrates only the files and subdirectories in the specified directories.
For example, you want to migrate only
root_dir/good_sub1/
androot_dir/good_sub2/
in theroot_dir/
directory. In this case, you can select this method and specifygood_sub1/
andgood_sub2/
.
Note- A directory name cannot start with a forward slash (/) or a backslash (\), and cannot contain double forward slashes (//), double periods (..), or double quotation marks ("). The character string that consists of all the specified directory names cannot exceed 10 KB in length.
- A directory name must end with a forward slash (/). For example, you can specify docs/ as a directory name.
- You can specify up to 20 directories that you want to include or exclude.
Migration Type Yes Select the data migration mode. Valid values: - Full: The system migrates all data from the source data address to the destination data address. You must configure the Start Time Point of File parameter. The system migrates all data whose last modification time is later than the specified time. After all data is migrated, the migration job ends.
If you change the data at the source data address after the migration job is complete, you can submit another job to migrate all data. In this case, the system migrates only the changed data.
- Incremental: The system runs a migration job based on the values that you specified for the Migration Interval and Migration Times parameters.
- You must configure the Start Time Point of File parameter. During the first migration, the system migrates all data whose last modification time is later than the specified time. After the first migration is complete, incremental migration is performed based on the value that you specified for the Migration Interval parameter. For each incremental migration, the system migrates only the data that is created or modified after the previous migration starts and before the current migration starts.
- If you set the Migration Times parameter to N, full migration is performed once and then incremental migration is performed (N - 1) times.
For example, the current time is 08:00, March 10, 2019 and you set the Migration Interval parameter to 1, the Migration Times parameter to 5, and the Start Time Point of File parameter to 08:00, March 5, 2019. When the first migration starts, the system migrates all files whose last modification time is between 08:00, March 5, 2019 and 08:00, March 10, 2019. In this example, the first migration requires one hour to complete and the second migration starts at 10:00, March 10, 2019. The duration from 08:00 to 10:00 consists of one hour for the first migration process and one hour for the migration interval. During the second migration, the system migrates the files whose last modification time is between 08:00, March 10, 2019 and 10:00, March 10, 2019. The migration job consists of one full migration and four incremental migrations.
Important Before full or incremental migration starts, the system compares the files at the source data address with the files at 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:- The Content-Type values of the source file and the destination file are different.
- The last modification time of the source file is later than that of the destination file.
- The size of the source file is different from that of the destination file.
Start Time Point of File Yes Specify a time to filter data to be migrated. Data will be migrated if it is created or modified after the specified time. Valid values: - All: migrates all files.
- Assign: migrates only the files that are created or modified after the specified time.
For example, if you set the time to 08:00:00, November 1, 2018, only the files that are created or modified after 08:00:00, November 1, 2018 are migrated.
Migration Interval This parameter is required if you set the Migration Type parameter to Incremental. The default value is 1, and the maximum value is 24. Unit: hours. Migration Times This parameter is required if you set the Migration Type parameter to Incremental. The default value is 1, and the maximum value is 30. File Overwrite Method Yes The method that is used to process the source file whose name is the same as that of a destination file. Valid values: - LastModified: If a source file has the same name as a destination file, the system compares the last modification time that is indicated by the LastModified property of the files.
- If the last modification time of the source file is later than that of the destination file, the source file is migrated and the destination file is overwritten.
- If the last modification time of the source file is earlier than that of the destination file, the source file is not migrated and the destination file is retained.
- If the two files have the same last modification time, the system checks the values of the Size and Content-Type properties of the files.
If the two files have the same Size and Content-Type values, the source file is not migrated. If the two files have different values of at least one property, the source file is migrated and the destination file is overwritten.
- Condition: If a source file has the same name as a destination file, the system compares the values of the LastModified, Size, and Content-Type properties of the two files.
- If all property values of the two files are the same, the source file is not migrated.
- If the two files have different values of at least one property, the source file is migrated and the destination file is overwritten.
- All: If a source file has the same name as a destination file, the system performs no comparison and directly overwrites the destination file with the source file.
- No: If a source file has the same name as a destination file, the system performs no comparison and directly skips the source file during the migration.
- In the Data Prediction section of the Performance step, configure the Data Size and File Count parameters. Note To ensure a successful migration, we recommend that you estimate the amount of data that you want to migrate as accurately as possible. For more information, see Estimate the amount of data that you want to migrate.
- Optional:In the Flow Control section of the Performance step, configure the Time Range and Max Flow(MB/s) parameters, and then click Add. Note To ensure business continuity, we recommend that you configure the Time Range and Max Flow parameters based on the workload peaks and troughs.
- Click Create and wait until the migration job is complete.
View the status of a data address
- Normal: The data address is created.
- Creating: The data address is being created. The first data address for the ECS instance requires approximately 3 minutes to create. If the data address remains in the Creating state for a long period of time, you can click Refresh in the upper-right corner to check the latest status of the data address.
- Invalid: An error occurred when the data address is being created. You can verify the configuration information and check whether Data Online Migration can access the shared files of the ECS instance. If the error persists, submit a ticket.