當oracle data guard中如主庫出現當機時,需要將從庫切換為主庫,以下從實驗環境模擬主從庫切換操作:

1.查看主從庫角色

192.168.88.120:

192.168.88.119:

2.將主庫(88.120)切換為從庫

alter database commit to switchover to physical standby with sessionB shutdown;

shutdown immediate;?
startup nomount;?
alter database mount standby database;

recover managed standby database disconnect;

?

3.主庫切換完成,開啟數據庫

alter database open或shutdown以后startup

4..將從庫切換為主庫

alter database commit to switchover to primary;

shutdown immediate

startup

5.在從庫上應用重做日志

alter database recover managed standby database disconnect from session;

6..查看切換后狀態

192.168.88.119:

?

192.168.88.120:

7..驗證切換是否成功(角色切換過來后需要查看日志是否能正確從新的主庫同步到備用庫)

在主從庫上分別執行

SELECT SEQUENCE#,APPLIED FROM V$ARCHIVED_LOG ORDER BY SEQUENCE#;

新主庫88.119:

新從庫88.120:

通過主從庫新的歸檔應用和確認狀態可查看到兩個庫的角色已經成功切換!

? ? ?本文轉自ttzztt 51CTO博客，原文鏈接：http://blog.51cto.com/tianzt/263522，如需轉載請自行聯系原作者