OCP-1Z0-053-V12.02-618题

618.You want to set the following initialization parameters for your database instance:
LOG_ARCHIVE_DEST_1 = 'LOCATION=/disk1/arch'
LOG_ARCHIVE_DEST_2 ='LOCATION=/disk2/arch'
LOG_ARCHIVE_DEST_3 = 'LOACTION=/disk3/arch'
LOG_ARCHIVE_DEST_4 = 'LOCATION=/disk4/arch MANDATORY'
Identify the statement that correctly describes this setting.
A. The MANDATORY location must be a flash recovery area.
B. The optional destinations may not use the flash recovery area.
C. This setting is not allowed because the first destination is not set as MANDATORY.
D. The online redo log file is not allowed to be overwritten if the archived log cannot be created in the fourth destination.
Answer: D
答案解析：
参考：http://docs.oracle.com/cd/E11882_01/server.112/e41134/log_arch_dest_param.htm#SBYDB01109

MANDATORY

Specifies that filled online log files must be successfully archived to the destination before they can be reused.

If

MANDATORY

is not specified, then, by default, the destination is considered to be optional.
At least one destination must succeed, even if all destinations are optional. If archiving to an optional destination fails, the online redo log file is still available for reuse and may be overwritten eventually. However, if
the archival operation of a mandatory destination fails, online redo log files cannot be overwritten.