📖 What is AWS Database Migration Service (DMS)?
AWS Database Migration Service (DMS) facilitates secure and efficient migration of databases to AWS. It supports homogeneous migrations (e.g., Oracle to Oracle) and heterogeneous migrations (e.g., Oracle to Aurora). DMS minimizes downtime by continuously replicating data changes during the migration process.
"DMS supports both one-time migrations and continuous data replication. Understand the Schema Conversion Tool (SCT) which works in conjunction with DMS for heterogeneous migrations. Be aware of potential limitations and compatibility issues when migrating between different database engines."
📚 Certification: AWS Certified Solutions Architect - Associate (SAA-C03)
🔑 What are the Key Concepts of AWS Database Migration Service (DMS)?
- ▸ DMS uses replication instances to perform the migration, requiring careful sizing based on database size and change data capture (CDC) load.
- ▸ The Schema Conversion Tool (SCT) assesses source database schemas and automatically converts them to a format compatible with the target database.
- ▸ DMS supports various source and target databases, but not all combinations are fully supported; check AWS documentation for compatibility.
- ▸ Change Data Capture (CDC) enables near-zero downtime migrations by continuously replicating changes from the source to the target database.
- ▸ DMS tasks define the migration rules, including table mappings, transformations, and filtering criteria for selective data migration.
🎯 How does AWS Database Migration Service (DMS) appear on the SAA-C03 Exam?
You may be asked to identify the AWS service best suited for migrating a large, on-premises SQL Server database to Amazon Aurora with minimal downtime.
A scenario might describe a company needing to continuously replicate data from a MySQL database to a data warehouse in Amazon Redshift for reporting purposes – select the appropriate DMS configuration.
Expect questions about troubleshooting DMS task failures, focusing on replication instance sizing, network connectivity, and database permissions.
❓ Frequently Asked Questions
When would I use SCT alongside DMS?
SCT is crucial for heterogeneous migrations (e.g., Oracle to PostgreSQL). It converts the source database schema to be compatible with the target, addressing differences in data types and stored procedures.
What are the implications of choosing different replication instance sizes?
Undersized instances cause performance bottlenecks and migration delays. Oversized instances increase costs. Monitor CPU, memory, and network utilization during migration to optimize instance size.
Can DMS migrate data directly from one S3 bucket to another?
No, DMS is designed for database migrations. While it can *load* data *to* S3 as part of a migration, it doesn't directly transfer data between S3 buckets. Use S3 replication or other tools for that purpose.