Known issues and limitations for Amazon RDS Custom for Oracle - Amazon Relational Database Service

Known issues and limitations for Amazon RDS Custom for Oracle

When working with RDS Custom for Oracle, note the following issues and limitations for DB instances.

Known issues

Note the following issues for RDS Custom for Oracle:

  • Some RDS APIs can be blocked when a database instance is on an older AMI. To resolve this issue, patch your DB instance to the latest AMI using OS patching. For more information, see CEV upgrade options.

  • You must configure the crontab file after scale compute, OS upgrades, and other workflows where RDS Custom replaces the root volume. We highly recommend that you keep a backup of crontab.

  • You must declare the following initialization parameters in /rdsdbdata/config/oracle_pfile:

    • MEMORY_MAX_TARGET

    • MEMORY_TARGET

    • PGA_AGGREGATE_TARGET

    • PROCESSES

    • SGA_TARGET

    • USE_LARGE_PAGES

    If the preceding parameters aren't declared in /rdsdbdata/config/oracle_pfile, read replica creation and scale compute might fail.

Limitations

RDS Custom for Oracle has the following limitations:

  • You can't delete the symbolic links for configuration files such as the server parameter file, audit files, listener.ora, tnsnames.ora, or sqlnet.ora. You also can't modify the directory structure for these files. RDS Custom automation expects these files to exist in a specific directory structure.

    To create a server parameter file from an initialization parameter file, use the following syntax.

    CREATE SPFILE='/rdsdbdata/admin/$ORACLE_SID/pfile/spfile$ORACLE_SID.ora' FROM PFILE='/rdsdbdata/config/oracle_pfile';
  • You can't change the master username for your RDS Custom for Oracle DB instance by using the ModifyDBInstance API.

  • Control file multiplexing isn't currently supported because of a read replica issue. Before you create a read replica, make sure to specify only one filename in the CONTROL_FILES initialization parameter on the source database.

  • Comments aren't supported in a server parameter file or initialization parameter file.

  • You can't make more than 20 snapshot copies at the same time in the same Region.