Migrate full data from an Amazon RDS for Oracle database to an ApsaraDB RDS for PPAS database

Background information

• DTS uses read and write resources of the source and destination databases during full data migration. This may increase the loads of the database servers. If the database performance is unfavorable, the specification is low, or the data volume is large, database services may become unavailable. For example, DTS occupies a large amount of read and write resources in the following cases: a large number of slow SQL queries are performed on the source database, the tables have no primary keys, or a deadlock occurs in the destination database. Before you migrate data, evaluate the impact of data migration on the performance of the source and destination databases. We recommend that you migrate data during off-peak hours. For example, you can migrate data when the CPU utilization of the source and destination databases is less than 30%.
• The tables to be migrated in the source database must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.
• If a data migration task fails, DTS attempts to resume the task. In this case, before you switch your workloads to the destination database, you must stop or release the task. Otherwise, the data in the source database will overwrite the data in the destination database after the task is resumed.

Billing

Permissions required for database accounts

For more information about how to create and authorize database account, see the following topics:

• CREATE USER and GRANT for an Amazon RDS for Oracle database
• Create an account for an RDS for PPAS instance

Limits

• Incremental data migration is not supported, because the dbcreator and sysadmin roles required for incremental data migration are not available in Amazon RDS for Oracle.
• Do not perform DDL operations on the source database during full data migration because these operations cannot be synchronized.
• Migration of materialized views is not supported.
• During schema migration, reverse indexes and bitmap indexes are converted into common indexes. Partitioned indexes become indexes in each partitioned table of the ApsaraDB RDS for PPAS database.

Data type conversion

For more information, see Data type mappings between heterogeneous databases.

Preparation

1. Log on to the Amazon RDS Management Console.
2. Go to the Basic information page of the Amazon RDS for Oracle instance.
3. In the Security group rules section, click the name of the security group corresponding to the existing inbound rule.
   
4. On the Security groups page, click the Inbound tab in the Security group section. On the Inbound tab, click Edit to add the CIDR blocks of DTS servers in the corresponding region to the inbound rule. For more information, see Add the CIDR blocks of DTS servers to the security settings of on-premises databases.
   

   Note

   • You only need to add the CIDR blocks of DTS servers that reside in the same region as the destination database. For example, the source database resides in the Singapore (Singapore) region and the destination database resides in the China (Hangzhou) region. You only need to add the CIDR blocks of DTS servers that reside in the China (Hangzhou) region.
   • You can add all of the required CIDR blocks to the inbound rule at a time.

Procedure

1. Log on to the DTS console.
2. In the left-side navigation pane, click Data Migration.
3. At the top of the Migration Tasks page, select the region where the destination cluster resides.
   
4. In the upper-right corner of the page, click Create Migration Task.
5. Configure the source and destination databases.
   

   Section	Parameter	Description
   N/A	Task Name	DTS generates a random task name. However, we recommend that you specify an informative name to ease management.
   Source Database	Instance Type	Select User-Created Database with Public IP Address.
   	Instance Region	When the instance type is set to User-Created Database with Public IP Address, you do not need to set Instance Region.
   	Database Type	Select Oracle.
   	Hostname or IP Address	Enter the endpoint for accessing the Amazon RDS for Oracle database. Note You can obtain the endpoint on the Basic information page of the source Amazon RDS for MySQL instance.
   	Port Number	Enter the port number configured for the user-created Oracle database. The default port number is 1521.
   	Instance Type	Non-RAC Instance: If you select this option, you must specify the SID. RAC Instance: If you select this option, you must specify the Service Name.
   	Database Account	Enter the account for the Amazon RDS for MySQL database. For more information about permissions required for the account, see Permissions required for database accounts.
   	Database Password	Enter the password of the database account. Note After you specify the source database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the source database parameters based on the check results.
   Destination Database	Instance Type	Select RDS Instance.
   	Instance Region	Select the region where the destination ApsaraDB RDS for PPAS instance resides.
   	RDS Instance ID	Select the destination ApsaraDB RDS for PPAS instance ID.
   	Database Name	Enter the name of the destination database.
   	Database Account	Enter the database account of the destination ApsaraDB RDS for PPAS instance. For more information about permissions required for the account, see Permissions required for database accounts.
   	Database Password	Enter the password of the database account. Note After you specify the destination database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the destination database parameters based on the check results.

6. Click Set Whitelist and Next in the lower-right corner of the page.
   Note The IP addresses of DTS servers are automatically added to the whitelist of the destination RDS instance. Then, DTS servers can connect to the RDS instance.
7. Configure migration types and objects.
   

   Item	Description
   Migration types	Select Schema Migration and Full Data Migration. Note Incremental data migration is not supported because the dbcreator and sysadmin roles required for incremental data migration are not available in Amazon RDS for Oracle. To ensure data consistency, do not write new data into the Amazon RDS for MySQL instance during full data migration.
   Objects to be migrated	Select the objects to be migrated in the Available section and click to move them to the Selected section. Note Objects to be migrated can be databases, tables, or columns. By default, the selected objects are not renamed after the migration. If you want to rename the objects that are migrated to the destination instance, you can use the object name mapping feature provided by DTS. For more information about how to use this feature, see Object name mapping. If you use the object name mapping feature for an object, objects that depend on the object may fail to be migrated.

8. In the lower-right corner of the page, click Precheck.
   Notice

   • Before you can start the data migration task, a precheck is performed. DTS can migrate data only if the precheck is past.
   • If the precheck fails, click the icon next to each failed item to view details. Fix the issues as prompted and run the precheck again.
9. After the precheck is past, click Next.
10. In the Confirm Settings dialog box, specify the Channel Specification parameter and select Data Transmission Service (Pay-As-You-Go) Service Terms.
11. Click Buy and Start to start the data migration task.
    Note Do not manually stop a migration task. Otherwise, data migrated to the destination database will be incomplete. Wait until the data migration task stops when it is complete.

    
12. Switch your workloads to the destination ApsaraDB RRDS for PPAS database.