Redo Log Info - Quiz Explanation

The correct answers are indicated below, along with the text that explains the correct answers.

1.	Why does Oracle recommend multiplexing your redo log files, and storing each member on separate disks? Please select the best answer.
	A.	To use as many disks as possible, thus maximizing disk utilization
	B.	To preserve the redo log in the event that one disk is damaged
	C.	To increase the number of log switches
	D.	To concentrate all redo log input on one disk controller
	The correct answer is B. Redo logs are critical to database recovery, both after a system crashes and after you restore it. Multiplexing, or making multiple copies of your redo logs, greatly reduces the chance that you will lose a logfile in the event of a disk failure. If you make three copies of each redo log member and place those on three different disks, then you would need to lose all three disks in order to lose the redo log.

2.	Which of the following SQL queries will give you a list of your redo log files? Please select the best answer.
	A.	`SELECT log_file_name FROM dba_log_files;`
	B.	`SELECT member FROM v$log;`
	C.	`SELECT member FROM v$logfile;`
	D.	`SELECT log_member FROM V$LOG_FILES;`
	The correct answer is C: `SELECT member FROM v$logfile;.` The `V$LOGFILE` view returns the names of your redo log files. The member field is the one that contains the filename.