9 Common Issues With DMS in Amazon AWS

If you’re experiencing issues with AWS Database Migration Service (DMS), here are some common problems and potential solutions:

1. Connection Issues:
   • Verify that the source and target database endpoints are correctly configured in DMS.
   • Check network settings, security groups, and access control lists (ACLs) to ensure DMS can access both the source and target databases.
   • Ensure that the database credentials provided to DMS are correct and have the necessary permissions.
2. Performance Issues:
   • Performance can be affected by several factors, including network bandwidth, the size and type of the databases, and the instance type of the replication server.
   • Consider increasing the replication instance size for better performance.
   • Optimize your source and target database configurations for better read and write performance.
3. Data Not Replicating Correctly:
   • Ensure that the tables you are migrating have primary keys, as DMS relies on them for certain types of replication.
   • Check the task logs for errors or warnings that could indicate why data isn’t replicating as expected.
   • Review your task settings, including the mapping rules and selection rules.
4. Task Fails to Start or Stops Unexpectedly:
   • Check the task logs for any error messages.
   • Ensure that the replication instance has enough storage and CPU resources.
   • Verify that there are no issues with the source or target databases that could affect the migration task.
5. Issues with Specific Database Engines:
   • Some database engines may have specific requirements or limitations with AWS DMS. Consult the AWS DMS documentation for any engine-specific considerations.
   • Ensure that the version of your database engine is compatible with DMS.
6. Long Running Tasks and Resource Consumption:
   • Long-running migration tasks can consume significant resources. Monitor your replication instances and databases for high resource usage.
   • Consider setting up alerts for high CPU usage, storage space, or network throughput.
7. Schema Conversion Issues:
   • If you’re also using the AWS Schema Conversion Tool (SCT), ensure that it has correctly converted the source schema to be compatible with the target database.
   • Check for any manual conversion steps that need to be performed.
8. Incremental Data Sync Issues:
   • For ongoing replication tasks, ensure that the change data capture (CDC) functionality is set up correctly.
   • Verify that the necessary logging is enabled on the source database for CDC.
9. Cost Management:
   • Keep an eye on the costs associated with DMS, especially if you’re using a larger instance size or migrating large amounts of data.

For complex issues or specific error messages, consulting the AWS documentation or reaching out to AWS support can provide more detailed guidance. AWS DMS is a powerful service, but it requires careful configuration and monitoring to ensure a smooth migration process