什么是归档日志
归档日志(Archive Log)是非活动的重做日志备份.通过使用归档日志,可以保留所有重做历史记录,当数据库处于ARCHIVELOG模式并进行日志切换式,后台进程ARCH会将重做日志的内容保存到归档日志中.当数据库出现介质失败时,使用数据文件备份,归档日志和重做日志可以完全恢复数据库。
如何开启归档模式
查询是否开启归档
[oracle@osc ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Mon Nov 12 17:36:13 2018
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> archive log list;
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 1124
Current log sequence 1126
由上可见,数据库未开启归档
开启归档模式
SQL> shutdown immediate;
Database closed.
Database dismount