1. 首先來模擬 Gap 的產生 1.1. 備庫關閉： SYS@dgtest_sshutdown immediate; 1.2. 主庫切換日志 SYS@dgtestselect SEQUENCE#,ARCHIVED,STATUS from v$log; SEQUENCE# ARC STATUS ---------- --- ---------------- 61 YES ACTIVE 62 YES ACTIVE 63 NO CURREN

1. 首先來模擬Gap的產生

1.1. 備庫關閉：

SYS@dgtest_s>shutdown immediate;

1.2. 主庫切換日志

SYS@dgtest>select SEQUENCE#,ARCHIVED,STATUS from v$log;

SEQUENCE# ARC STATUS

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

61 YES ACTIVE

62 YES ACTIVE

63 NO CURRENT

SYS@dgtest>alter system archive log current;

System altered.

SYS@dgtest>select SEQUENCE#,ARCHIVED,STATUS from v$log;

SEQUENCE# ARC STATUS

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

64 NO CURRENT

62 YES ACTIVE

63 YES ACTIVE

剛才current的日志已經歸檔

1.3. 刪除歸檔，產生UNRESOLVABLE GAP

現在刪除63號歸檔

[oracle@primary arch]$ mv 1_63_909786801.dbf 1_63_909786801.dbf.bak

2. 查看報錯

2.1. 啟動備庫

SYS@dgtest_s>startup

2.2. 查看備庫的alert

Media Recovery Log /u01/app/oracle/arch/1_62_909786801.dbf

Media Recovery Waiting for thread 1 sequence 63

Fetching gap sequence in thread 1, gap sequence 63-63

Fri May 06 05:28:09 2016

FAL[client]: Failed to request gap sequence

GAP - thread 1 sequence 63-63

DBID 3866310445 branch 909786801

FAL[client]: All defined FAL servers have been attempted.

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

Check that the CONTROL_FILE_RECORD_KEEP_TIME initialization

parameter is defined to a value that's sufficiently large

enough to maintain adequate log switch information to resolve

archivelog gaps.

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

2.3. 主庫查詢SWITCHOVER_STATUS

SYS@dgtest>SELECT SWITCHOVER_STATUS FROM V$DATABASE;

SWITCHOVER_STATUS

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

UNRESOLVABLE GAP

為UNRESOLVABLE GAP，說明此時的GAP需要我們自己手工去修復，無法自動修復，可自動修復的GAP顯示為RESOLVABLE

GAP

3. 基于SCM的增量備份修復GAP

3.1. 在備庫上查詢current scn號

SYS@dgtest_s>select current_scn from v$database;

CURRENT_SCN

-----------

2567388

3.2. 到主庫去進行基于此SCN的增量備份

RMAN> BACKUP INCREMENTAL FROM SCN 2567388 DATABASE FORMAT '/u01/app/oracle/oradata/tmp/ora11_scn_%U' tag 'For Standby Gap';

3.3. 傳輸到備庫：

[oracle@primary tmp]$ scp * standby:/u01/app/oracle/oradata/tmp

oracle@standby's password:

ora11_scn_0kr54hvk_1_1 100% 125MB 125.2MB/s 00:01

ora11_scn_0lr54l99_1_1 100% 9664KB 9.4MB/s 00:00

3.4. 備庫重新啟動到mount，并取消日志應用

SYS@dgtest_s>shutdown immediate;

SYS@dgtest_s>startup mount;

SYS@dgtest_s>alter database recover managed standby database cancel;

3.5. 注冊剛才傳輸過來的備份集

RMAN> CATALOG START WITH '/u01/app/oracle/oradata/tmp';

3.6. recover備庫

RMAN> recover database noredo;

恢復完畢，這時我們可以觀察備庫的alert日志：

Incremental restore complete of datafile 4 /u01/app/oracle/oradata/dgtest_s/users01.dbf

checkpoint is 2893208

last deallocation scn is 3

Incremental restore complete of datafile 3 /u01/app/oracle/oradata/dgtest_s/undotbs01.dbf

checkpoint is 2893208

last deallocation scn is 973300

Incremental restore complete of datafile 5 /u01/app/oracle/oradata/dgtest_s/example01.dbf

checkpoint is 2893208

last deallocation scn is 942056

Mon May 09 05:20:25 2016

Incremental restore complete of datafile 2 /u01/app/oracle/oradata/dgtest_s/sysaux01.dbf

checkpoint is 2893208

last deallocation scn is 956093

Incremental restore complete of datafile 1 /u01/app/oracle/oradata/dgtest_s/system01.dbf

checkpoint is 2893208

last deallocation scn is 955346

發現數據文件的scn號都已經重新刷新，但是此時還不能重新起庫，需要重新從主庫生成一個standby controlfile。

3.7. 主庫備份控制文件

RMAN> BACKUP CURRENT CONTROLFILE FOR STANDBY FORMAT '/u01/app/oracle/oradata/tmp/ctl.bak';

3.8. 傳輸standby控制文件到備庫

oracle@standby's password:

ctl.bak 100% 9664KB 9.4MB/s 00:00

3.9. 備庫恢復standby控制文件

備庫庫起到nomount階段：

SYS@dgtest_s>shutdown immediate

SYS@dgtest_s>startup nomount;

rman恢復控制文件

RMAN> RESTORE STANDBY CONTROLFILE FROM '/u01/app/oracle/oradata/tmp/ctl.bak';

3.10. mount備庫，并取消日志應用

SYS@dgtest_s> alter database mount;

SYS@dgtest_s>alter database recover managed standby database cancel;

3.11. 清空備庫日志組

SYS@dgtest_s>ALTER DATABASE CLEAR LOGFILE GROUP 1;

Database altered.

注：如果采用了standby log模式，不需要清空，如果清空會出現

SQL> ALTER DATABASE CLEAR LOGFILE GROUP 1;

ALTER DATABASE CLEAR LOGFILE GROUP 1

*

ERROR at line 1:

ORA-19527: physical standby redo log must be renamed

ORA-00312: online log 1 thread 1: '/u01/oradata/badly9/redo01.log'

說明：如果沒有采用standby log模式，有幾組需要清空幾組

3.12. 備庫重設flashback

SYS@dgtest_s>ALTER DATABASE FLASHBACK OFF;

SYS@dgtest_s>ALTER DATABASE FLASHBACK ON;

3.13. 備庫開始應用日志

SYS@dgtest_s>ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;

4. 確認修復成功

在主庫中執行

SYS@dgtest>alter system switch logfile;

分別主備庫中執行select max(sequence#) from v$archived_log;如果一致標示修復成功

SYS@dgtest>select max(sequence#) from v$archived_log;

MAX(SEQUENCE#)

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

81

SYS@dgtest_s>select max(sequence#) from v$archived_log;

MAX(SEQUENCE#)

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

81

至此GAP修復完畢。

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