Which three are true about Exadata Smart Flash Log? 

Answer options:

A. Databases on the Database Machine use Exadata Smart Flash Log by default.
B. I/O Resource Manager database plans can be used to enable or disable Exadata Smart Flash Log for individual databases.
C. LGWR will not wait for writes to Exadata Smart Flash Log if the write to a disk-based logfile completes first.
D. I/O Resource Manager category plans can be used to enable or disable Exadata Smart Flash Log for different I/O categories.
E. The use of Exadata Smart Flash Logs is mandatory for support of production databases.

ABC

A: Exadata I/O Resource Manager (IORM) has been enhanced to enable or disable Smart Flash Logging for the different databases running on the Database Machine, reserving flash for the most performance critical databases. B: The Exadata I/O Resource Manager (IORM) has been enhanced to enable or disable Smart Flash Logging for the different databases running on the Database Machine. C: Smart Flash Logging works as follows. When receiving a redo log write request, Exadata will do parallel writes to the on-disk redo logs as well as a small amount of space reserved in the flash hardware. When either of these writes has successfully completed the database will be immediately notified of completion. If the disk drives hosting the logs experience slow response times, then the Exadata Smart Flash Cache will provide a faster log write response time. Conversely, if the Exadata Smart Flash Cache is temporarily experiencing slow response times (e.g., due to wear leveling algorithms), then the disk drive will provide a faster response time. This algorithm will significantly smooth out redo write response times and provide overall better database performance. Incorrect Answers: D: Category plans are configured and enabled using the CellCLI utility on the cell. Only one category plan can be enabled at a time. References: http://structureddata.org/2011/10/12/exadata-smart-flash-logging-explained/