Working with storage in RDS for Oracle - Amazon Relational Database Service
ConsiderationsLimitationsDatabase management operations

Working with storage in RDS for Oracle

Every RDS for Oracle instance has a primary storage volume. To increase storage capacity, you can attach up to three additional storage volumes to your DB instance. Depending on your workload requirements, choose between gp3 and io2 storage for each volume. For example, you might put frequently accessed data on an io2 volume and historical data on a gp3 volume.

Use additional storage volumes to enable the following benefits:

  • Enhanced capacity – Scale your total storage up to 256 TiB per DB instance by attaching up to three additional storage volumes.

  • Flexible storage configuration and performance optimization – Mix different storage types (gp3 and io2) to optimize for both cost and performance based on your data access patterns. Separate frequently accessed data on high-performance io2 storage from archival data on cost-effective gp3 storage.

  • Expand and reduce storage capacity as needed – Attach a volume when you need additional storage, as during data migration, and then later delete the volume. In this way, you can expand and reduce the total DB instance storage.

  • Online data movement – Use the built-in capabilities of Oracle database to move data between volumes without downtime.

Note

You can remove additional storage volumes, but you can't remove the primary volume.

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Considerations for using additional storage volumes with RDS for Oracle

Consider the following when using additional storage volumes with RDS for Oracle:

  • You can add up to 3 additional storage volumes per instance.

  • Additional storage volumes must use the following volume names:

    • rdsdbdata2

    • rdsdbdata3

    • rdsdbdata4

  • You can only add General Purpose SSD (gp3) and Provisioned IOPS SSD (io2) storage types.

  • You can use Oracle’s online relocation capabilities to move data between volumes while your applications continue running.

  • When you create an additional storage volume by modifying the DB instance, RDS immediately creates the storage volume regardless of the schedule modifications setting. Adding a storage volume is an online operation and does not impact your database performance. See Using the schedule modifications setting.

For optimal performance, check the following when you are using additional storage volumes:

  • Data movement planning

    • Schedule large movements during off-peak hours

    • Break large operations into smaller chunks

    • Monitor system resources during moves

  • Resource management

    • Keep sufficient free space on both volumes

    • Monitor I/O patterns using AWR or Statspack

    • Watch for storage-full scenarios

  • Best practices

    • Use online datafile relocation operations where possible

    • Maintain appropriate indexes

    • Regularly monitor space usage

When using additional storage volumes with replicas:

  • When you are creating an RDS for Oracle replica for a DB instance that has additional storage volumes, RDS automatically configures additional storage volumes on the replica. However, any subsequent modifications made in storage volumes of your primary DB instance are not automatically applied to the replica.

  • When managing datafile locations across volumes, we recommend using parameter group settings instead of session-level changes to ensure consistent behavior between primary and replica instances.

Limitations of using additional storage volumes with RDS for Oracle

The following limitations apply to using additional storage volumes with RDS for Oracle:

  • You can’t add a storage volume to the instance types with less than 64GiB memory because they don’t have sufficient memory to support large storage volumes.

  • The minimum storage size is 200GiB for additional storage volumes. The primary storage volume of your DB instance should be equal to or larger than 200GiB to attach additional storage volumes. The maximum storage size for your DB instance is 256 TiB total across all volumes.

  • The following capabilities aren’t supported for DB instances with additional storage volumes:

    • Cross-region automated backups

    • Cross-region read replica

    • Storage autoscaling (for additional storage volumes)

    • Cross-account snapshot copy

    • Public snapshots

  • You can't delete the primary storage volume (rdsdbdata), but you can delete other additional storage volumes as long as they're empty.

Database management operations with additional storage volumes in RDS for Oracle

You can perform database management operations such as creating tablespaces or moving data between storage volumes while using additional storage volumes in RDS for Oracle. For more information about database management operations with additional storage volumes, see the following sections: