1Z0-053 争议题目解析682

1Z0-053 争议题目解析682

考试科目：1Z0-053
题库版本：V13.02

题库中原题为：

682.Identify the scenarios in which the RMAN CROSSCHECR command is useful. (Choose all that
apply.)
A.To check that the obsolete backups are deleted from the repository records and from the disk.
B.To update the RMAN repository if you delete archived redo logs with operating system commands.
C.To update outdated information about backups that disappeared from disk or tape or became corrupted
and inaccessible.
D.To synchronize the actual files on disk or in the media management catalog with the RMAN repository
for which the backup was not taken using RMAN.
Answer:AD

争议点：
网上有人说选择BC，比如“标记为正确答案，不看answer版”题库。

比如：
Riveore的解析：http://blog.csdn.net/rlhua/article/details/14191401

LuiseDalian的解析：http://blog.itpub.net/17013648/viewspace-1346722/

B，CROSSCHECK用来检查归档，假如归档被删除，那么到了备份归档的时候，rman会检查归档的连续性，如果归档不连续，则无法备份，
那么dba就要执行crosscheck archivelog来检查，然后才能够继续备份归档，当然归档不连续，就无法做完全恢复，需要及时的备份数据库
C，rman的CROSSCHECK命令一种用途就是用来同步知识库与备份片的信息，假如备份片被意外删除，或者备份片所在的带库损坏无法访问，
那么就可以用crosscheck命令来检查，备份片损坏的相应的备份集的信息就会被删除

初步结论：
选择BC。