在Oracle数据库的开发环境和测试环境中,数据库的日志模式和自动归档模式一般都是不设置的,这样有利于系统应用的调整,也免
在Oracle数据库的开发环境和测试环境中,数据库的日志模式和自动归档模式一般都是不设置的,这样有利于系统应用的调整,也免的生成大量的归档日志文件将磁盘空间大量的消耗。但在系统上线,成为生产环境时,将其设置为日志模式并自动归档就相当重要了,因为,这是保证系统的安全性,有效预防灾难的重要措施。这样,通过定时备份数据库和在两次备份间隔之间的日志文件,可以有效的恢复这段时间的任何时间点的数据,可以在很多时候挽回或最大可能的减少数据丢失。虽然Oracle数据库的日志模式和自动归档设置并不复杂,但其中的一些概念和操作过程还是容易混淆的,现在根据本人的经验,,分析介绍如下,所用环境为UNIX(HPUX,SOLARIES,AIX,TRU64UNIX)和Oracle8.
一要使OARCLE数据库进行日志的自动归档,需要做两方面的事情,一是数据库日志模式的设置(database log mode,可为Archive Mode和No Archive Mode),另外就是自动归档模式设置(Automatic archival,可为Enabled和Disabled)。 二如何查看数据库的现行日志和自动归档模式的设置:
可用archive log list命令来查看。
例如:
运行在日志自动归档模式下的数据库系统查看结果如下(一般是生产环境)
SVRMGR> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /backup/archivelog
Oldest online log sequence 2131
Next log sequence to archive 2133
Current log sequence 2133
没有启动数据库日志模式和自动归档的数据库系统查看结果如下(一般是测试环境)
SVRMGR> archive log list
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination /u01/app/Oracle/product/8.0.5/dbs/arch
Oldest online log sequence 194
Current log sequence 196

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