Q139. While backing up to the Oracle Fast Recovery Area (FRA), you determined the backup is taking too long and suspect a performance bottleneck.
Which three are true about diagnosing and tuning these problems? (Choose three.)
- A. If an RMAN BACKUP VALIDATE command takes roughly the same time as an actual backup, thenboth read and write I/O are likely bottlenecks.
- B. Setting DBWR_IO_SLAVES to a non zero value can improve backup performance when usingsynchronous I/O.
- C. If an RMAN BACKUP VALIDATE command takes noticeably less than an actual backup, then writeI/O is a likely bottleneck.
- D. If an RMAN BACKUP VALIDATE command takes roughly the same time as an actual backup, thenread I/O is a likely bottleneck.
- E. Data files with a high value in V$BACKUP_SYNC_IO.DISCRETE_BYTES_PER_SECOND are a potential performance bottleneck when synchronous I/O is used.
- F. Setting DBWR_IO_SLAVES to a non zero value can improve backup performance when usingasynchronous I/O/
- G. Data files with a high value in V$BACKUP_ASYNC_IO.SHORT_WAITS are a potential performance bottleneck when asynchronous I/O is used.
Answer: B,C,D