【DG】利用閃回數據庫（flashback）修復Failover後的DG環境

利用閃回數據庫（flashback）修復Failover後的DG環境

 

1.1  BLOG文檔結構圖

 

 

 

1.2  前言部分

1.2.1  導讀和注意事項

各位技術愛好者，看完本文後，你能夠掌握以下的技能，也能夠學到一些其它你所不知道的知識，~O(∩_∩)O~：

① Failover後DG環境的恢復方法（重點）

② DG的基本維護操做

③ GC客戶端軟件的安裝

④ 利用GC快速搭建一套DG環境

⑤ Failover和Switchover的區別

⑥ 其它維護操做

 

Tips：

① 本文在itpub（http://blog.itpub.net/26736162）、博客園(http://www.cnblogs.com/lhrbest)和微信公衆號（xiaomaimiaolhr）上有同步更新。

② 文章中用到的全部代碼、相關軟件、相關資料及本文的pdf版本都請前往小麥苗的雲盤下載，小麥苗的雲盤地址見：http://blog.itpub.net/26736162/viewspace-1624453/。

③ 若網頁文章代碼格式有錯亂，請下載pdf格式的文檔來閱讀。

④ 在本篇BLOG中，代碼輸出部分通常放在一行一列的表格中。

⑤ 本文適合於初中級人員閱讀，數據庫大師請略過本文。

⑥ 不喜勿噴。

本文若有錯誤或不完善的地方請你們多多指正，您的批評指正是我寫做的最大動力。

1.3  本文簡介

10月23和24日考完了OCM，感受過關的法則就是「真題+多練」，練習過10來遍，基本就能夠考過了。OCM的考試內容除了GC這塊小麥苗沒有接觸過，其它內容基本都算熟。基本命令熟記於心，不熟的命令能夠立馬找到官方文檔，善用OEM和SQL Developer工具。因此，想快速經過OCM考試的朋友能夠私下聯繫小麥苗，小麥苗會把本身的經驗全都教給你們。

好了，廢話很少說了。最近小麥苗的DBA寶典微信羣裏，有朋會友問到了Failover操做後，如何恢復到最初的DG環境。這個問題，小麥苗大概知道利用閃回能夠實現，只是沒有作過實驗，或者曾經作過實驗，只是沒有記錄文檔，反正就是年紀大了，想不起來了。好吧，最近就抽個時間把這個實驗作一遍。有不對的地方，依然請你們指出。

 

1.4  相關知識點掃盲

① 物理DG的Switchover切換：http://blog.itpub.net/26736162/viewspace-1753111/

② 物理DG的Failover切換：http://blog.itpub.net/26736162/viewspace-1753130/

③ 利用閃回數據庫（flashback）修復Failover後的DG環境：http://blog.itpub.net/26736162/viewspace-2146883/

④ Switchover和Failover的區別：http://blog.itpub.net/26736162/viewspace-2141207/

 

 

 

 

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第二章 實驗準備

2.1  實驗環境介紹

實驗環境爲練習OCM的虛擬機環境：

項目	Source DB	Target DB
DB 類型	單機	單機
DB VERSION	11.2.0.3.0	11.2.0.3.0
DB 存儲	FS	FS
OS版本及kernel版本	OEL linux 5.4 32	OEL linux 5.4 32
DB_NAME	PROD1	PROD1
ORACLE_SID	PROD1	SBDB1
ORACLE_HOME	/u01/app/oracle/product/11.2.0/dbhome_1	/u01/app/oracle/product/11.2.0/db_1
hosts文件	10.190.104.111  edsir4p1.us.oracle.com edsir4p1 10.190.104.28   edsir1p8.us.oracle.com edsir1p8

2.2  實驗目標

備庫執行FAILOVER後，經過閃回數據庫技術從新恢復DG環境，而不用從新搭建DG。

2.3  實驗過程

 

2.4  利用GC快速搭建DG環境

小麥苗手頭的DG環境是在一個主機上，測試多有不便，恰好，最近練習OCM的環境還在，就用練習OCM的環境來作這個實驗吧。若已經有DG環境的朋友能夠略過該小節內容。

2.4.1  安裝GC客戶端軟件

一、起動GC服務器，首先確保EMREP數據庫處於OPEN狀態，監聽也已經啓動，GC服務器啓動日誌爲：/u01/app/gc_inst/em/EMGC_OMS1/sysman/log/emctl.log

cd /u01/app/oracle/Middleware/oms11g/bin

./emctl start oms

[oracle@edsir1p8- ~]$ ps -ef|grep pmon oracle    4763     1  0 00:53 ?        00:00:00 ora_pmon_EMREP oracle   11802 11633  0 01:39 pts/2    00:00:00 grep pmon [oracle@edsir1p8- ~]$ cd /u01/app/ gc_inst/      Middleware/   oracle/       oraInventory/ [oracle@edsir1p8- ~]$ cd /u01/app/Middleware/oms11g/bin [oracle@edsir1p8- bin]$ ./emctl start oms Oracle Enterprise Manager 11g Release 1 Grid Control  Copyright (c) 1996, 2010 Oracle Corporation.  All rights reserved. Starting WebTier... WebTier Successfully Started Starting Oracle Management Server... Oracle Management Server Successfully Started AdminServer Could Not Be Started Oracle Management Server is Up [oracle@edsir1p8- bin]$ more /etc/hosts # Do not remove the following line, or various programs # that require network functionality will fail. 127.0.0.1       localhost.localdomain   localhost 10.190.104.28   edsir1p8.us.oracle.com  edsir1p8 10.190.104.111 edsir4p1.us.oracle.com edsir4p1 [oracle@edsir1p8- bin]$ ./emctl status oms -details Oracle Enterprise Manager 11g Release 1 Grid Control  Copyright (c) 1996, 2010 Oracle Corporation.  All rights reserved. Enter Enterprise Manager Root (SYSMAN) Password : Console Server Host : edsir1p8.us.oracle.com HTTP Console Port   : 7788 HTTPS Console Port  : 7799 HTTP Upload Port    : 4889 HTTPS Upload Port   : 4900 OMS is not configured with SLB or virtual hostname Agent Upload is locked. OMS Console is locked. Active CA ID: 1

 

 

 

二、安裝agent

https://10.190.104.28:4900/agent_download/  從這裏下載

 

 

 

右鍵保存到桌面。

a、在須要安裝agent的機器上mkdir /u01/app/agentbase 建立目錄，並將agentDownload.linux文件cp到/u01/app/agentbase目錄下，而且賦予可執行權限。

b、在服務端OMS啓動的狀況下，在客戶端執行：

./agentDownload.linux -b /u01/app/agentbase -m edsir1p8.us.oracle.com -r 7799 -y

       安裝過程當中要輸入偶數機上OMS的密碼

c、安裝完成要用root執行：

[root@edsir4p1 ~]# sudo /u01/app/agentbase/agent11g/root.sh

沒有root密碼要使用sudo執行，注意：必定要執行該腳本，它會設置一些文件的權限（該腳本會把$AGENT_HOME/bin/nm*的幾個文件的全部者修改成root。）。若是不執行，那麼搭建DG可能會報錯：「ERROR: NMO not setuid-root (Unix-only)」

d、進入/u01/app/agentbase/agent11g/bin 

./emctl status agent  檢查同步狀態

./emctl upload agent  上傳同步

./emctl secure agent  從新註冊agent，用於安裝時密碼輸錯

 

過程以下所示：

[oracle@edsir4p1-PROD2 ~]$ mkdir -p /u01/app/agentbase [oracle@edsir4p1-PROD2 ~]$ cd /u01/app/agentbase [oracle@edsir4p1-PROD2 agentbase]$ cp /home/oracle/Desktop/agentDownload.linux . [oracle@edsir4p1-PROD2 agentbase]$ chmod +x agentDownload.linux  [oracle@edsir4p1-PROD2 agentbase]$ ll total 40 -rwxr-xr-x 1 oracle oinstall 38525 Nov  6 01:46 agentDownload.linux [oracle@edsir4p1-PROD2 agentbase]$ ./agentDownload.linux agentDownload.linux invoked on Mon Nov  6 01:46:55 UTC 2017 with Arguments "" agentDownload.linux: Invalid Invocation Usage: agentDownload.linux -b[cdhimnoprtuvxyNR]    b - Base installation location for Agent Oracle home    d - Do NOT initiate automatic target discovery    h - Usage (this message)    i - Inventory pointer location file    l - To specify as local host (pass -local to runInstaller)    m - Management Service host name for downloading the Management Agent software    n - Cluster name    o - Old Oracle Home location during Upgrade    p - Static port list file    r - Port for connecting to the Management Service host    t - Do NOT start the Agent    u - Upgrade    v - Inventory directory location    x - Debug output    c - CLUSTER_NODES    N - Do NOT prompt for Agent Registration Password    R - To use virtual hostname(ORACLE_HOSTNAME) for this installation. If this is being used along with more than one cluster nodes through -c option, then -l option also needs to be passed.    y - Decline Security Updates. [oracle@edsir4p1-PROD2 agentbase]$ ./agentDownload.linux -b /u01/app/agentbase -m edsir1p8.us.oracle.com -r 7799 -y agentDownload.linux invoked on Mon Nov  6 01:49:01 UTC 2017 with Arguments "-b /u01/app/agentbase -m edsir1p8.us.oracle.com -r 7799 -y" Platform=Linux.i686, OS=linux GetPlatform:returned=0, and os is set to: linux, platform=Linux.i686 Creating /u01/app/agentbase/agentDownload11.1.0.1.0Oui ... LogFile for this Download can be found at: "/u01/app/agentbase/agentDownload11.1.0.1.0Oui/agentDownload.linux110617014901.log" Running on Selected Platform: Linux.i686 Installer location: /u01/app/agentbase/agentDownload11.1.0.1.0Oui Downloading Agent install response file ... Downloading Agent install response file ... Executing wget_get_file  。。。。。。。。。。省略部分。。。。。。 Finished Downloading agent_download.rsp with Status=0 Response file check Complete - Success Checking the writable permission for baseDir - passed   Provide the Agent Registration password so that the Management Agent can communicate with Secure Management Service. Note: You may proceed with the installation without supplying the password; however, Management Agent can be secured manually after the installation. If Oracle Management Service is not secured, agent will not be secured, so continue by pressing Enter Key.   Enter Agent Registration Password:      <<<<=輸入密碼 Downloading Oracle Installer ... Executing wget_get_file  https://edsir1p8.us.oracle.com:7799/agent_download/11.1.0.1.0/linux/oui/oui_linux.jar using the url https://edsir1p8.us.oracle.com:7799/agent_download/11.1.0.1.0/ to access OMS 。。。。。。。。。。省略部分。。。。。。 Configuration assistant "Agent Configuration Assistant" Succeeded   AgentPlugIn:agent configuration finished with status = true   Running Configuration assistant "Agent Add-on Plug-in"   Configuration assistant "Agent Add-on Plug-in" Succeeded   Querying Agent status: Agent is running Removing the copied stuff..... Removed: /u01/app/agentbase/agentDownload11.1.0.1.0Oui/oui_linux.jar Removed: /u01/app/agentbase/agentDownload11.1.0.1.0Oui/agent_download.rsp Removed:/u01/app/agentbase/agentDownload11.1.0.1.0Oui/Disk1 Log name of installation can be found at: "/u01/app/agentbase/agentDownload.linux110617014901.log" /u01/app/agentbase/agent11g/root.sh needs to be executed by root to complete this installation. [oracle@edsir4p1-PROD2 agentbase]$ sudo /u01/app/agentbase/agent11g/root.sh [oracle@edsir4p1-PROD2 agentbase]$ ll total 80 drwxr-xr-x 40 oracle oinstall  4096 Nov  6 01:53 agent11g drwxr-xr-x  2 oracle oinstall  4096 Nov  6 01:53 agentDownload11.1.0.1.0Oui -rwxr-xr-x  1 oracle oinstall 38525 Nov  6 01:46 agentDownload.linux -rw-r--r--  1 oracle oinstall    78 Nov  6 01:46 agentDownload.linux110617014655.log -rw-r--r--  1 oracle oinstall 24908 Nov  6 01:53 agentDownload.linux110617014901.log [oracle@edsir4p1-PROD2 agentbase]$ cd agent11g/bin/ [oracle@edsir4p1-PROD2 bin]$ ./emctl status agent Oracle Enterprise Manager 11g Release 1 Grid Control 11.1.0.1.0 Copyright (c) 1996, 2010 Oracle Corporation.  All rights reserved. --------------------------------------------------------------- Agent Version     : 11.1.0.1.0 OMS Version       : 11.1.0.1.0 Protocol Version  : 11.1.0.0.0 Agent Home        : /u01/app/agentbase/agent11g Agent binaries    : /u01/app/agentbase/agent11g Agent Process ID  : 26954 Parent Process ID : 26914 Agent URL         : https://edsir4p1.us.oracle.com:3872/emd/main/ Repository URL    : https://edsir1p8.us.oracle.com:4900/em/upload Started at        : 2017-11-06 01:53:15 Started by user   : oracle Last Reload       : 2017-11-06 01:53:15 Last successful upload                       : 2017-11-06 01:55:13 Total Megabytes of XML files uploaded so far :    17.86 Number of XML files pending upload           :        0 Size of XML files pending upload(MB)         :     0.00 Available disk space on upload filesystem    :    83.54% Last successful heartbeat to OMS             : 2017-11-06 01:57:20 --------------------------------------------------------------- Agent is Running and Ready [oracle@edsir4p1-PROD2 bin]$

 

 

2.4.2  使用GC快速搭建物理備庫

從瀏覽器打開https://10.190.104.28:7799/em/，使用sysman用戶進行登陸。

 

 

 

使用sys用戶登陸PROD1數據庫。

 

 

 

 

 

 

等待大約10分鐘便可自動完成DG的搭建和配置工做。期間，能夠查看主庫和備庫的告警日誌以及數據文件夾的大小來預估搭建完成時間。

 

建立完成後：

 

2.4.3  啓用實時應用

 

 

2.5  開啓主備庫閃回

主庫：

SQL> select name, open_mode, database_role, flashback_on from v$database;   NAME      OPEN_MODE            DATABASE_ROLE    FLASHBACK_ON --------- -------------------- ---------------- ------------------ PROD1     READ WRITE           PRIMARY          NO SQL>  select INSTANCE_NAME,INSTANCE_ROLE from v$instance;   INSTANCE_NAME    INSTANCE_ROLE ---------------- ------------------ PROD1            PRIMARY_INSTANCE

 

備庫：

SQL> select name, open_mode, database_role, flashback_on from v$database;   NAME      OPEN_MODE            DATABASE_ROLE    FLASHBACK_ON --------- -------------------- ---------------- ------------------ PROD1     READ ONLY WITH APPLY PHYSICAL STANDBY NO SQL> select INSTANCE_NAME,INSTANCE_ROLE from v$instance;   INSTANCE_NAME    INSTANCE_ROLE ---------------- ------------------ SBDB1            PRIMARY_INSTANCE

 

 

主庫開啓閃回：

SQL> alter database flashback on;   Database altered.   SQL>  select name, open_mode, database_role, flashback_on from v$database;   NAME      OPEN_MODE            DATABASE_ROLE    FLASHBACK_ON --------- -------------------- ---------------- ------------------ PROD1     READ WRITE           PRIMARY          YES SQL> select oldest_flashback_scn, to_char(oldest_flashback_time,'yyyy-mm-dd HH24:mi:ss') oldest_flashback_time from v$flashback_database_log;   OLDEST_FLASHBACK_SCN OLDEST_FLASHBACK_TI -------------------- -------------------               867005 2017-11-06 02:55:59   SQL> show parameter flashback   NAME                                 TYPE        VALUE ------------------------------------ ----------- ------------------------------ db_flashback_retention_target        integer     1440   ====>參數db_flashback_retention_target控制閃回時間範圍，數字單位是分鐘，默認爲1天。這個數字決定了閃回的時間範圍，若是設置更長的時間，對應的閃回日誌文件大小就會比較大一些。

 

告警日誌：

Mon Nov 06 02:55:55 2017 alter database flashback on Starting background process RVWR Mon Nov 06 02:55:56 2017 RVWR started with pid=37, OS id=1096 Allocated 3981204 bytes in shared pool for flashback generation buffer Flashback Database Enabled at SCN 867006 Completed: alter database flashback on

 

此時，備庫並無開啓閃回，須要在備庫上手動開啓閃回：

SQL> alter database flashback on; alter database flashback on * ERROR at line 1: ORA-01153: an incompatible media recovery is active     SQL> recover managed standby database cancel; Media recovery complete. SQL>  alter database flashback on;   Database altered.   SQL> select name, open_mode, database_role, flashback_on from v$database;   NAME      OPEN_MODE            DATABASE_ROLE    FLASHBACK_ON --------- -------------------- ---------------- ------------------ PROD1     READ ONLY            PHYSICAL STANDBY YES   SQL> alter database recover managed standby database using current logfile disconnect from session;   Database altered.

 

 

第三章 實驗1

實驗1、PROD1意外宕機，SBDB1執行Failover操做變爲主庫；而後將PROD1利用閃回數據庫功能閃回到SBDB1變爲主庫的SCN時間點，而後將PROD1轉換爲備庫，最後利用switchover轉換爲最初的環境。<===PROD1須要開啓閃回

3.1  Failover操做

切換以前確保監聽使用靜態監聽、fal_client、fal_server、log_archive_dest_1和log_archive_dest_2參數已正確配置。

主庫操做：

SYS@PROD1> select dbid,name,current_scn,protection_mode,protection_level,database_role,force_logging,open_mode,switchover_status from v$database;         DBID NAME       CURRENT_SCN PROTECTION_MODE      PROTECTION_LEVEL     DATABASE_ROLE    FOR OPEN_MODE            SWITCHOVER_STATUS ---------- ---------- ----------- -------------------- -------------------- ---------------- --- -------------------- -------------------- 2177200393 PROD1           868787 MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  PRIMARY          YES READ WRITE           TO STANDBY SYS@PROD1> create table test_bylhr as select * from dba_objects;   Table created.   SYS@PROD1> insert into test_bylhr select * from test_bylhr;   72459 rows created.   SYS@PROD1> commit;   Commit complete.   SYS@PROD1> select count(1) from test_bylhr;     COUNT(1) ----------     144918   SYS@PROD1> shutdown abort ORACLE instance shut down.

 

 

備庫操做：

SYS@SBDB1> select count(1) from test_bylhr;     COUNT(1) ---------- 144918   SYS@SBDB1> alter database recover managed standby database cancel;   Database altered.   SYS@SBDB1> alter database recover managed standby database finish;   Database altered.   SYS@SBDB1> set line 9999 SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   READ ONLY            PHYSICAL STANDBY SESSIONS ACTIVE      SBDB1   SYS@SBDB1>  alter database commit to switchover to primary with session shutdown;   Database altered.   SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   MOUNTED              PRIMARY          NOT ALLOWED          SBDB1   SYS@SBDB1> alter database open;   Database altered.

 

 

3.2  Primary從新加入

Failover後的Primary數據庫，實際上已經失去了和DG的關聯，若是Primary故障嚴重，是難以保障對應的歸檔數據能夠順利傳輸的。若是但願Primary從新回到DG環境，關鍵就是恢復的時間點。要求Primary回到Standby切換角色的那個時間點，理論上就能夠「延續」操做。

3.2.1  查詢原備庫變爲新主庫的SCN

在原備庫端，查看v$database視圖，能夠看到這個庫成爲primary的具體時間。

SYS@SBDB1> select STANDBY_BECAME_PRIMARY_SCN from v$database;   STANDBY_BECAME_PRIMARY_SCN --------------------------                     869428     SYS@SBDB1> create table test_bylhr2 as select * from dba_objects where rownum<=1000;   Table created.   SYS@SBDB1> alter system switch logfile;   System altered. SYS@SBDB1> select count(1) from test_bylhr2;     COUNT(1) ----------       1000   SYS@SBDB1> select dbms_flashback.get_system_change_number from dual;   GET_SYSTEM_CHANGE_NUMBER ------------------------                   869833

 

 

3.2.2  原主庫執行閃回操做

SYS@PROD1> startup mount ORACLE instance started.   Total System Global Area  313860096 bytes Fixed Size                  1336232 bytes Variable Size             247467096 bytes Database Buffers           58720256 bytes Redo Buffers                6336512 bytes Database mounted. SYS@PROD1> flashback database to scn 869428;   Flashback complete.   SYS@PROD1> select dbid,name,current_scn,protection_mode,protection_level,database_role,force_logging,open_mode,switchover_status from v$database;         DBID NAME       CURRENT_SCN PROTECTION_MODE      PROTECTION_LEVEL     DATABASE_ROLE    FOR OPEN_MODE            SWITCHOVER_STATUS ---------- ---------- ----------- -------------------- -------------------- ---------------- --- -------------------- -------------------- 2177200393 PROD1                0 MAXIMUM PERFORMANCE  UNPROTECTED          PRIMARY          YES MOUNTED              NOT ALLOWED

 

 

注意：從新加入的原Primary是不能恢復角色的，而是隻能先成爲Standby角色。應用後續的日誌達到同步。

SYS@PROD1> alter database convert to physical standby;   Database altered.   SYS@PROD1> startup force;         ORACLE instance started.   Total System Global Area  313860096 bytes Fixed Size                  1336232 bytes Variable Size             247467096 bytes Database Buffers           58720256 bytes Redo Buffers                6336512 bytes Database mounted. Database opened. SYS@PROD1> select dbid,name,current_scn,protection_mode,protection_level,database_role,force_logging,open_mode,switchover_status from v$database;         DBID NAME       CURRENT_SCN PROTECTION_MODE      PROTECTION_LEVEL     DATABASE_ROLE    FOR OPEN_MODE            SWITCHOVER_STATUS ---------- ---------- ----------- -------------------- -------------------- ---------------- --- -------------------- -------------------- 2177200393 PROD1           869428 MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  PHYSICAL STANDBY YES READ ONLY            TO PRIMARY SYS@PROD1> alter database recover managed standby database using current logfile disconnect from session;   Database altered. SYS@PROD1> select count(1) from test_bylhr2;     COUNT(1) ----------       1000

 

 

Oracle DG在發生Failover以後，當主庫解決問題，是不能夠直接回到DG環境的。這個過程每每須要一些輔助組建的配合。如RMAN、Flashback，均可以簡化重回DG的過程時間。

 

注意：若是原主庫查詢不到test_bylhr2表的數據，則須要仔細檢查監聽使用靜態監聽、fal_client、fal_server、log_archive_dest_1和log_archive_dest_2參數已正確配置。

 

3.3  執行switchover切換成初始環境

新主庫：

SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   READ WRITE           PRIMARY          TO STANDBY           SBDB1 SYS@SBDB1> alter database commit to switchover to physical standby with session shutdown;   Database altered.   SYS@SBDB1> shutdown immediate ORA-01507: database not mounted     ORACLE instance shut down. SYS@SBDB1> startup mount ORACLE instance started.   Total System Global Area  313860096 bytes Fixed Size                  1336232 bytes Variable Size             239078488 bytes Database Buffers           67108864 bytes Redo Buffers                6336512 bytes Database mounted. SYS@SBDB1>  select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   MOUNTED              PHYSICAL STANDBY TO PRIMARY           SBDB1

 

 

新備庫執行：

SYS@PROD1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME   LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME ------ ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1  ARCHIVELOG   READ ONLY            PHYSICAL STANDBY TO PRIMARY           PROD1   SYS@PROD1> alter database commit to switchover to primary with session shutdown;   Database altered.   SYS@PROD1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME   LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME ------ ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1  ARCHIVELOG   MOUNTED              PRIMARY          NOT ALLOWED          PROD1   SYS@PROD1> alter database open;   Database altered.   SYS@PROD1>  select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME   LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME ------ ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1  ARCHIVELOG   READ WRITE           PRIMARY          RESOLVABLE GAP       PROD1 SYS@PROD1> create table test_bylhr3 as select * from dual;   Table created.

 

備庫查詢：

SYS@SBDB1> select * from test_bylhr3; select * from test_bylhr3               * ERROR at line 1: ORA-01219: database not open: queries allowed on fixed tables/views only     SYS@SBDB1> alter database open;   Database altered.   SYS@SBDB1> select * from test_bylhr3;   D - X

 

 

至此，該實驗完畢。即主備庫執行Failover後，經過閃回從新恢復最初的DG環境。

 

第四章 實驗2

實驗2、PROD1意外宕機，SBDB1執行Failover操做變爲主庫；而後將SBDB1利用閃回數據庫功能閃回到SBDB1變爲主庫的SCN時間點，此時SBDB1仍然是主庫的角色，而後將SBDB1轉換爲備庫。<===SBDB1須要開啓閃回，會丟失部分數據。

4.1  Failover操做

主庫操做：

SYS@PROD1>  select dbid,name,current_scn,protection_mode,protection_level,database_role,force_logging,open_mode,switchover_status from v$database;         DBID NAME   CURRENT_SCN PROTECTION_MODE      PROTECTION_LEVEL     DATABASE_ROLE    FOR OPEN_MODE            SWITCHOVER_STATUS ---------- ------ ----------- -------------------- -------------------- ---------------- --- -------------------- -------------------- 2177200393 PROD1       901700 MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  PRIMARY          YES READ WRITE           TO STANDBY   SYS@PROD1> create table test_bylhr4 as select * from dual;   Table created.   SYS@PROD1> select * from test_bylhr4;   D - X   SYS@PROD1> shutdown abort ORACLE instance shut down.

 

 

備庫操做：

SYS@SBDB1> select * from test_bylhr4;   D - X   SYS@SBDB1> alter database recover managed standby database finish force;   Database altered.   SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   MOUNTED              PHYSICAL STANDBY TO PRIMARY           SBDB1   SYS@SBDB1>  alter database commit to switchover to primary with session shutdown;   Database altered.   SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   MOUNTED              PRIMARY          NOT ALLOWED          SBDB1   SYS@SBDB1>  select * from test_bylhr4; select * from test_bylhr4                * ERROR at line 1: ORA-01219: database not open: queries allowed on fixed tables/views only     SYS@SBDB1> alter database open;   Database altered.   SYS@SBDB1> select * from test_bylhr4;   D - X   SYS@SBDB1>  create table test_bylhr5 as select * from dual;   Table created.   SYS@SBDB1>  select * from test_bylhr5;   D - X

 

 

4.2  新主庫閃回

SYS@SBDB1> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SYS@SBDB1> startup mount ORACLE instance started.   Total System Global Area  313860096 bytes Fixed Size                  1336232 bytes Variable Size             243272792 bytes Database Buffers           62914560 bytes Redo Buffers                6336512 bytes Database mounted. SYS@SBDB1>  select STANDBY_BECAME_PRIMARY_SCN from v$database;   STANDBY_BECAME_PRIMARY_SCN --------------------------                     901723   SYS@SBDB1>  flashback database to scn 901723;   Flashback complete.   SYS@SBDB1> select * from test_bylhr5; select * from test_bylhr5               * ERROR at line 1: ORA-01219: database not open: queries allowed on fixed tables/views only     SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   MOUNTED              PRIMARY          NOT ALLOWED          SBDB1   SYS@SBDB1>  alter database convert to physical standby;   Database altered.   SYS@SBDB1> shutdown immediate ORA-01507: database not mounted     ORACLE instance shut down. SYS@SBDB1> startup mount ORACLE instance started.   Total System Global Area  313860096 bytes Fixed Size                  1336232 bytes Variable Size             243272792 bytes Database Buffers           62914560 bytes Redo Buffers                6336512 bytes Database mounted. SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   MOUNTED              PHYSICAL STANDBY TO PRIMARY           SBDB1   SYS@SBDB1> alter database open;   Database altered.   SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   READ ONLY            PHYSICAL STANDBY TO PRIMARY           SBDB1   SYS@SBDB1> SYS@SBDB1> alter database recover managed standby database using current logfile disconnect from session;   Database altered.   SYS@SBDB1>  select * from test_bylhr5; select * from test_bylhr5                * ERROR at line 1: ORA-00942: table or view does not exist     SYS@SBDB1> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;   NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME --------- ------------ -------------------- ---------------- -------------------- ------------------------------ PROD1     ARCHIVELOG   READ ONLY WITH APPLY PHYSICAL STANDBY SESSIONS ACTIVE      SBDB1

 

 

4.3  原主庫打開

SYS@PROD1> startup force ORACLE instance started.   Total System Global Area  313860096 bytes Fixed Size                  1336232 bytes Variable Size             251661400 bytes Database Buffers           54525952 bytes Redo Buffers                6336512 bytes Database mounted. Database opened. SYS@PROD1> create table test_bylhr6 as select * from dual;   Table created.   SYS@PROD1> select * from test_bylhr6;   D - X

 

 

備庫查詢：

SYS@SBDB1> select * from test_bylhr6;   D - X

 

DGMGRL中查看配置：

DGMGRL> show  CONFIGURATION VERBOSE;   Configuration - PROD1.us.oracle.com     Protection Mode: MaxPerformance   Databases:     PROD1 - Primary database     SBDB1 - Physical standby database   Fast-Start Failover: DISABLED   Configuration Status: SUCCESS

 

說明直接在原備庫上執行閃回操做也可讓Failover後的環境從新恢復最初的環境。不過這也意味着部分數據的丟失。

第五章 實驗總結

一、主庫在開啓閃回數據庫功能後，備庫並不會開啓閃回數據庫的功能。

二、PROD1爲主庫，SBDB1爲備庫；若PROD1意外宕機，則SBDB1執行Failover操做變爲主庫；此時若想恢復DG環境，則有3種處理辦法：

① 將PROD1利用閃回數據庫功能閃回到SBDB1變爲主庫的SCN時間點，而後將PROD1轉換爲備庫，最後利用switchover轉換爲最初的環境。<===PROD1須要開啓閃回

② 將SBDB1利用閃回數據庫功能閃回到SBDB1變爲主庫的SCN時間點，此時SBDB1仍然是主庫的角色，而後將SBDB1轉換爲備庫。<===SBDB1須要開啓閃回，會丟失部分數據。

③ 利用RMAN從新搭建DG環境。詳情請參考：http://blog.itpub.net/26736162/viewspace-1753130/

第六章 參考文章

 

6.1  MOS或官網

https://docs.oracle.com/cd/E11882_01/server.112/e41134/scenarios.htm#SBYDB4889

https://docs.oracle.com/cd/E11882_01/server.112/e41134/scenarios.htm#SBYDB00900

This chapter describes scenarios you might encounter while administering your Data Guard configuration. Each scenario can be adapted to your specific environment.聽Table 13-1lists the scenarios presented in this chapter.

Table 13-1 Data Guard Scenarios

Reference	Scenario
Section 13.1	Configuring Logical Standby Databases After a Failover
Section 13.2	Converting a Failed Primary Into a Standby Database Using Flashback Database
Section 13.3	Using Flashback Database After Issuing an Open Resetlogs Statement
Section 13.4	Recovering After the NOLOGGING Clause Is Specified
Section 13.5	Creating a Standby Database That Uses OMF or Oracle ASM
Section 13.6	Recovering From Lost-Write Errors on a Primary Database
Section 13.7	Converting a Failed Primary into a Standby Database Using RMAN Backups
Section 13.8	Changing the Character Set of a Primary Without Re-Creating Physical Standbys

 

這8個實驗，建議有興趣的朋友都作一遍。

http://blog.itpub.net/24500180/viewspace-1068495/

http://blog.itpub.net/24500180/viewspace-1068141/

http://blog.itpub.net/24500180/viewspace-1069602/

 

13.2 Converting a Failed Primary Into a Standby Database Using Flashback Database

After a failover occurs, the original primary database can no longer participate in the Data Guard configuration until it is repaired and established as a standby database in the new configuration. To do this, you can use the Flashback Database feature to recover the failed primary database to a point in time before the failover occurred, and then convert it into a physical or logical standby database in the new configuration. The following sections describe:

• Flashing Back a Failed Primary Database into a Physical Standby Database

• Flashing Back a Failed Primary Database into a Logical Standby Database

  Note:

  You must have already enabled Flashback Database on the original primary database before the failover. See  Oracle Database Backup and Recovery User's Guide for more information.

• Flashing Back a Logical Standby Database to a Specific Applied SCN

  See Also:

  Oracle Data Guard Broker for automatic reinstatement of the failed primary database as a new standby database (as an alternative to using Flashback Database)

 

13.2.1 Flashing Back a Failed Primary Database into a Physical Standby Database

The following steps assume that a failover has been performed to a physical standby database and that Flashback Database was enabled on the old primary database at the time of the failover. This procedure brings the old primary database back into the Data Guard configuration as a physical standby database.

Step 1   Determine the SCN at which the old standby database became the primary database.

On the new primary database, issue the following query to determine the SCN at which the old standby database became the new primary database:

SQL> SELECT TO_CHAR(STANDBY_BECAME_PRIMARY_SCN) FROM V$DATABASE;

Step 2   Flash back the failed primary database.

Shut down the old primary database (if necessary), mount it, and flash it back to the value for STANDBY_BECAME_PRIMARY_SCN that was determined in Step 1.

SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP MOUNT;
SQL> FLASHBACK DATABASE TO SCN standby_became_primary_scn;

Step 3   Convert the database to a physical standby database.

Perform the following steps on the old primary database:

1. Issue the following statement on the old primary database:

   SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY;
   

   This statement will dismount the database after successfully converting the control file to a standby control file.

2. Shut down and restart the database:

   SQL> SHUTDOWN IMMEDIATE;
   SQL> STARTUP MOUNT;
   

Step 4   Start transporting redo to the new physical standby database.

Perform the following steps on the new primary database:

1. Issue the following query to see the current state of the archive destinations:

   SQL> SELECT DEST_ID, DEST_NAME, STATUS, PROTECTION_MODE, DESTINATION, -
   > ERROR,SRL FROM V$ARCHIVE_DEST_STATUS;
   

2. If necessary, enable the destination:

   SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_n=ENABLE;
   

3. Perform a log switch to ensure the standby database begins receiving redo data from the new primary database, and verify it was sent successfully. Issue the following SQL statements on the new primary database:

   SQL> ALTER SYSTEM SWITCH LOGFILE;
   SQL> SELECT DEST_ID, DEST_NAME, STATUS, PROTECTION_MODE, DESTINATION,- 
   > ERROR,SRL FROM V$ARCHIVE_DEST_STATUS;
   

   On the new standby database, you may also need to change the LOG_ARCHIVE_DEST_n initialization parameters so that redo transport services do not transmit redo data to other databases.

Step 5   Start Redo Apply on the new physical standby database.

Issue the following SQL statement on the new physical standby database:

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE -
> USING CURRENT LOGFILE DISCONNECT;

Redo Apply automatically stops each time it encounters a redo record that is generated as the result of a role transition, so Redo Apply will need to be restarted one or more times until it has applied beyond the SCN at which the new primary database became the primary database. Once the failed primary database is restored and is running in the standby role, you can optionally perform a switchover to transition the databases to their original (pre-failure) roles. See Section 8.2.1, "Performing a Switchover to a Physical Standby Database" for more information.

6.2  博客

 

Data Guard高級玩法：經過閃回恢復failover備庫：http://blog.itpub.net/23718752/viewspace-2124234/

使用Flashback讓Failover數據庫從新加入DG環境：http://blog.itpub.net/17203031/viewspace-1184082

 

http://blog.itpub.net/24500180/viewspace-1068495/

http://blog.itpub.net/24500180/viewspace-1068141/

http://blog.itpub.net/24500180/viewspace-1069602/

 

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