The best practice for data files in Oracle ACFS is to use a clusterwide resource for the Oracle ACFS File system that stores the data files. For additional information, refer to "Creating Oracle ACFS Resources".
If the data files are added after the database installation is complete, you must modify the database dependencies to list the new Oracle ACFS file system. Failure to do so results in errors with application reliability. To specify the file systems in the dependency list, use the SRVCTL database object command to modify the Oracle ACFS paths used by the resource.
Oracle ACFS in Oracle Grid 12c Release 1 (12.1) supports all database files starting with Oracle Database 11g Release 2 (11.2.0.4), except for data files and redo logs in an Oracle Restart (standalone server) configuration. Oracle ACFS can be configured for use with the database particularly to leverage Oracle ACFS snapshots for database testing and development. To support database files, the COMPATIBLE.ADVM attribute must be set to 12.1 or higher for the disk group that contains the Oracle ACFS file system.
Support for database data files on Windows begins with Oracle Grid 12c Release 1 (12.1.0.2). For support of database files on Windows, the COMPATIBLE.ADVM attribute must be set to 12.1.0.2 or higher.
Support for database data files on Oracle Exadata (Linux) begins with Oracle Grid 12c Release 1 (12.1.0.2). However, Oracle ACFS does not currently have the ability to push database operations directly into storage.
Oracle ACFS additionally supports all database files for Oracle Database 10g Release 2 (10.2.0.4 and 10.2.0.5) on Oracle Exadata (Linux) storage only. For database file support with Oracle Database 10g Release 2 (10.2.0.4 and 10.2.0.5) on Oracle Exadata storage, the following conditions must be met:
When creating an Oracle Database with DBCA, you must set the REMOTE_LISTENER initialization parameter to your_scan_vip:1521 otherwise DBCA fails during the create process. For information about the REMOTE_LISTENER initialization parameter, refer to Oracle Database Reference.
You must modify all the start and stop dependencies of the database instance resources to ensure that the resources start when starting Oracle Clusterware. For information about resource dependencies, refer to Oracle Clusterware Administration and Deployment Guide.
The following list provides important information about using Oracle ACFS with database files:
Oracle ACFS support includes all file types supported by Oracle ASM. For a list of file types supported by Oracle ASM, refer to Table 5-1.
Oracle ACFS does not support data files or redo logs in an Oracle Restart configuration. Oracle ACFS does not support direct I/O in an Oracle Restart configuration.
When storing database data files on Oracle ACFS, you must set the FILESYSTEMIO_OPTIONS initialization parameter to setall; other settings are not supported. To achieve optimal performance with database data files, set ASM and ADVM compatibility attributes to 12.1 or higher for the disk group that contains the Oracle ADVM volume intended to hold the data files. For volumes created before 12.1.0.2, set the stripe columns to 1, or set the stripe columns to 8 and the stripe width to 1 MB. Volumes created while running 12.1.0.2 or higher already default to the high performance configuration (stripe columns = 8 and stripe width = 1 MB). For information about creating a volume, refer to "volcreate".
To obtain optimal database performance with snapshots, the snapshots must be created after the ADVM compatibility attribute is set to 12.1 or higher.
Use a 4 K or larger database block size and tablespace block size with Oracle ACFS for best performance.
If a data file is configured to automatically extend, then the size of the increments should be large enough to ensure that the extend operation occurs infrequently. Frequent automatic extends have a negative performance impact.
Running a workload in a snapshot reduces resources for the primary workload running on the base files because the storage is shared between the base file system and the snapshots. To run test scenarios in Oracle ACFS snapshots without impacting the primary workload, copy the file system and then run test workloads on snapshots created in the copied file system.
Using Oracle ACFS replication or encryption with database files on Oracle ACFS is not supported. For information about other replication options for database files on Oracle ACFS, refer to Oracle Data Guard Concepts and Administration and Oracle GoldenGate documentation. Oracle GoldenGate is an Oracle product sold independently of the Oracle Database. To encrypt database data files on Oracle ACFS, Oracle recommends Oracle Advanced Security. Oracle Advanced Security provides Transparent Data Encryption (TDE) to encrypt data files for entire tablespaces. For information about Transparent Data Encryption (TDE), refer to Oracle Database Advanced Security Guide.