20151230 053 60-b20
61.report need backup days 5;
即所列的文件需要5天以前的归档日志，也就是说5天内没有备份过
62.
retention plicy是指rman备份保留策略
configure retention policy to redundancy 1;
表示备份的冗余度为1，就是保留最近一次的备份(可以做数据库恢复需要的一次备份，比如全备)
configure retention policy to recovery window of 60days
表示备份的可恢复天数在60天以内的恢复所要的备份都保留
定义了保留策略之后可以用crosscheck backup和delete obsolete来删除不需要的备份
crosscheck backup
用于核对数据库、表空间、数据文件、控制文件、归档日志、spfile的备份集
67.asm实例由参数文件控制，其方式与常规数据库实例相同。
instance_type他应该设置为asm，表示asm实例。这是唯一一个必须定义的参数，对于数据库实例，
该参数设置为rdbms
asm_power_limit控制重新平衡操作的速度。值的范围从1到11,11表示最快。如如果省略，默认为1
68.alter diskgroup dg1 undrop disks
69.which statement about performing user-managed backups in a 24*7 envirment is true
c.to backup a tablespace.it must be in backupo mode
手工人备份，先将数据库或表空间置为备份模式，然后开始os拷贝，最后结束备份模式
71.obsolete 备份集只能通过report的方式列出，而不能用List查看
73.which two are the prerequisites to enable flashback data archive?
b.automatic undo managment must be enabled
d.the tablespace on which the flashback data archive is created must be management with automatic
segment space management
关键词是automatic
自动空间管理要开启
77.which are correct about database transpotation?
d.the compatible parameter must be set to 10.0.0.0 or higher and the database must be opened in
read-only mode before being transported
e.recovery manager(rman) is used to convert the necessary data files of the database if the target platform is different and has diffenrt endian format
78.DB_BLOCK_CHECKING specifies whether or not oracle performs block checking for database blocks calues
off or false
no block checking is perform for blocks in user tablespaces.however ,sermantic block checking forsystem tablespoace blocks is always
turned on
o LOW
Basic block header checks are performedafter block contents change in memory (for example, after UPDATE or INSERT statements,on-disk reads, or inter-instance block transfers in Oracle RAC).
o MEDIUM
All LOW checks and fullsemantic checks are performed for all objects except indexes (whose contentscan be reconstructed by a drop+rebuild on encountering a corruption).
o FULL or TRUE
All LOW and MEDIUM checksand full semantic checks are performed for all objects.
c.automatic memery management is enabled in an asm instance even when the memery_target parameter is not set
explitly
因为asm实例默认启用自动内存管理，即使未明确设置memeory_target参数也是如此
d.an rdbms instance gets connected to an asm instance using asmb as a foregroud process hwen
the database instance is started
数据库实例与asm之间的交互使用asmb数据库进程接收新文件的区映射
80.alter falshback archive fla1 modify retention 3 years
b.all historical data older than 3 years is purged from the flashback archive fla1
81.job_style=>'lightweight' 轻量型作业
it creates less metadata for jobs