How to search the appropriate solution for data migration

While the AI response mentioned the criteria (volume, time, network), the tool for this specific scenario is AWS DataSync.

• AWS DataSync: This is the primary managed service for migrating "a lot of files" from on-premises file servers (via NFS, SMB, or HDFS) to Amazon S3.
• Pros: It is up to 10x faster than open-source tools, handles data encryption, performs automatic data validation (checksums), and manages folder structures/metadata seamlessly.
• Use Case: Ideal for large-scale migrations and recurring sync tasks.

For Case 1 (Oracle to S3), ensure you choose Parquet or Avro as the target format in DMS if you plan to analyze the data later with tools like Amazon Athena. This is much more efficient than plain CSV.

If you require higher consistency or are considering a move to Amazon RDS for Oracle (instead of just S3), the following native methods are often superior to AWS DMS:

1. Oracle Data Guard to EC2 (Intermediate Step)

• Method: Set up an Oracle Standby Database on an Amazon EC2 instance using Oracle Data Guard.

• Process: Once the EC2 standby is synchronized with your on-premise source, you can perform a switchover with near-zero downtime. From EC2, you can then migrate to RDS using Data Pump or internal replication.

This is the most robust way to ensure 100% data parity and handles complex data types better than DMS.

2. RMAN Backup via Amazon EFS

• Method: Perform a native RMAN backup and store the backup pieces on Amazon EFS (Elastic File System).

• Process:

1. Mount the same EFS volume to your on-premise server and your Amazon RDS instance (using the EFS_INTEGRATION option).

2. Use the DBMS_DATAPUMP or RMAN restore procedures within RDS to import the data directly from the mounted EFS.

For large databases and avoids the overhead of network-based row-by-row insertion.

3. Oracle Data Pump (Direct to S3/EFS)

• Method: Export your schema via expdp and move the dump files to S3 or EFS.

• Process: RDS for Oracle can integrate directly with S3. You can download the dump files to the RDS DATA_PUMP_DIR and import them using the dbms_datapump package.

Important Note: Why EFS is Superior to S3 for RDS Imports

When performing an Oracle Data Pump import into Amazon RDS, I highly recommend using Amazon EFS (Elastic File System) instead of S3 !!!

• Avoid Storage Bloat: When you use the S3 integration to import data, you typically have to download the dump files from S3 to the local DATA_PUMP_DIR on your RDS instance. This consumes your allocated RDS storage volume, often forcing you to over-provision or scale the volume just to hold the temporary migration files.

• Direct Access: By using EFS Integration for RDS, you can mount the EFS file system directly. The RDS instance reads the dump files "in place" from EFS.

• Cost & Efficiency: Since EFS is a separate, elastic storage, you don't waste expensive, high-performance RDS (IOPS) storage for static dump files. Once the import is finished, you simply unmount or delete the files from EFS without having to "shrink“an oversized RDS volume (which is NOT supported yet for RDS Oracle).

PS: Keep in mind that Oracle Data Guard requires Oracle Enterprise Edition. If you are on Standard Edition, you might need to look at DBVisit or sticking with DMS/Data Pump.

For your data migration requirements, here are the recommended AWS solutions:

For Case 1 - CDC from On-Premise Oracle to Amazon S3:

AWS Database Migration Service (DMS) is indeed the recommended solution for your use case. For ongoing replication with minimal downtime from Oracle, you should use AWS DMS with full load and Change Data Capture (CDC) capabilities. This approach allows continuous replication of changes from your source Oracle database.

To implement this solution, you'll need to:

• Configure your Oracle database as a source by enabling supplemental logging and granting appropriate permissions
• Set up AWS DMS to access Oracle redo logs for continuous replication (using either Oracle LogMiner or AWS DMS Binary Reader)
• Configure Amazon S3 as your target endpoint

If you also need to convert database schemas or objects, AWS offers schema conversion solutions through either AWS DMS Schema Conversion (a fully managed console experience) or the downloadable AWS Schema Conversion Tool. These tools automatically assess and convert source database schemas and code objects to formats compatible with your target.

For Case 2 - File Transfer to Amazon S3:

When choosing the appropriate migration method for transferring files, you should consider several factors:

• Time allocated for data transfers
• Volume of data to be migrated
• Available network speeds
• Number of repetitive steps required
• Whether there are unique requirements per data store

For large-scale file transfers, you can evaluate options based on your existing infrastructure investments and whether managed services would be more beneficial than self-managed tooling. The decision should factor in your organization's time and performance requirements, data volumes, and network capabilities.

I recommend using a structured decision framework that evaluates these factors to determine the most suitable migration method and tool for your specific file transfer scenario.
Sources
Choosing a migration method - An Overview of AWS Cloud Data Migration Services
Use AWS DMS to migrate data between Amazon RDS for Oracle and different databases | AWS re:Post
AWS Schema Conversion Tool - Amazon Web Services