Which two are true about the Archive (ARCn) processes?
A)They archive redo directly from the redo log buffer.
B)They are used during instance recovery.
C)They automatically delete obsolete archive logs to make space for new archive logs.
D)They are enabled only when the database is in ARCHIVELOG mode.
E)They create archivelogs after every log switch.
Answer: DE
Zhao:
A Translation: They directly from the redo log buffer Archive redo.
For option A, the ARCn process archives online Redo log files, not redo log buffer.
For option B, the ARCn process does not work during instance recovery.
For the C option, the ARCn process does not have this effect.
After the log switch occurs, the archive process (ARCn) will copy the redo log files to the specified storage device. ARCn is an optional background process. The ARCn process only exists when the database is in ARCHIVELOG mode and automatic archiving is enabled.
If the archiving workload is expected to be heavy (for example, during batch loading of data), the number of large archiving processes can be increased. In addition, there can be multiple archive log destinations. It is recommended that there is at least one archiving process for each target location. The default setting is four archiving processes.