一、環境描述

Oracle 12c 單實例DataGuard

Rhel 7.3

二、測試過程

主庫操作

1.關閉DG,切換日誌

SQL> alter system set log_archive_dest_state_2=defer;

System altered.

SQL> show parameter log_archive_dest_state_2

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

log_archive_dest_state_2 string DEFER

log_archive_dest_state_20 string enable

log_archive_dest_state_21 string enable

log_archive_dest_state_22 string enable

log_archive_dest_state_23 string enable

log_archive_dest_state_24 string enable

log_archive_dest_state_25 string enable

log_archive_dest_state_26 string enable

log_archive_dest_state_27 string enable

log_archive_dest_state_28 string enable

log_archive_dest_state_29 string enable

SQL> alter system switch logfile;

System altered.

SQL> alter system switch logfile;

System altered.

SQL>

2.rman刪除歸檔

RMAN> list archivelog all;

List of Archived Log Copies for database with db_unique_name ORCL

=====================================================================

Key Thrd Seq S Low Time

------- ---- ------- - --------------------

40 1 31 A 26-NOV-2017 19:15:13

Name: /oracle/arch/1_31_958415134.dbf

42 1 32 A 26-NOV-2017 19:22:34

Name: /oracle/arch/1_32_958415134.dbf

RMAN> delete noprompt archivelog all;

released channel: ORA_DISK_1

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=39 device type=DISK

RMAN-08137: WARNING: archived log not deleted, needed for standby or upstream capture process

archived log file name=/oracle/arch/1_32_958415134.dbf thread=1 sequence=32

List of Archived Log Copies for database with db_unique_name ORCL

=====================================================================

Key Thrd Seq S Low Time

------- ---- ------- - --------------------

40 1 31 A 26-NOV-2017 19:15:13

Name: /oracle/arch/1_31_958415134.dbf

deleted archived log

archived log file name=/oracle/arch/1_31_958415134.dbf RECID=40 STAMP=961096954

Deleted 1 objects

RMAN>

三、小結

當我們DG環境，人為或者異常情況導致DG異常，沒有被應用的歸檔日誌是不會被刪除的。這裏可能會出現一個問題就是

當我們的磁盤空間緊張，可能生成大量的日誌占滿磁盤，導致數據庫無法寫入的問題。需要我們有監控系統，發現DG異常及時處理

，千萬不要等著影響業務才被動的去處理。

12c DataGuard 無法刪除歸檔日誌