DataGuard 日常操作-02

Dataguard採用最大效能模式.

第一部分 日常維護

一 正確開啟主庫和備庫
1 主庫:
SQL> startup mount

SQL> alter database archivelog;

SQL> alter database open;

2 備庫:
SQL> startup mount

SQL> alter database recover managed standby database disconnect from session;

OR =>> alter database recover managed standby database using current logfile disconnect from session;

二 正確關閉順序
1 備庫:
SQL> alter database recover managed standby database cancel;
SQL> shutdown immediate;

2 主庫
SQL>shutdown immediate;

三 備庫Read-Only模式開啟
當前主庫正常OPEN狀態
備庫處於日誌傳送狀態.

1 在備庫停止日誌傳送
SQL> recover managed standby database cancel;

2 備庫Read-only模式開啟
SQL> alter database open read only;

3 備庫回到日誌傳送模式
SQL> recover managed standby database disconnect from session;
Media recovery complete.
SQL> select status from v$instance;

STATUS
------------
MOUNTED

四 日誌傳送狀態監控

1 主庫察看當前日誌狀況
SQL> select sequence#,status from v$log;

SEQUENCE# STATUS
---------- ----------------
51 ACTIVE
52 CURRENT
50 INACTIVE

2 備庫察看RFS(Remote File Service)接收日誌情況和MRP應用日誌同步主庫情況
SQL> SELECT PROCESS, STATUS, THREAD#, SEQUENCE#, BLOCK#, BLOCKS FROM V$MANAGED_STANDBY;

PROCESS STATUS THREAD# SEQUENCE# BLOCK# BLOCKS
--------- ------------ ---------- ---------- ---------- ----------
ARCH CONNECTED 0 0 0 0
ARCH CONNECTED 0 0 0 0
RFS RECEIVING 0 0 0 0
MRP0 WAIT_FOR_LOG 1 52 0 0
RFS RECEIVING 0 0 0 0
可以看到備庫MPR0正等待SEQUENCE#為52的redo.

3 察看備庫是否和主庫同步
SQL> SELECT ARCHIVED_THREAD#, ARCHIVED_SEQ#, APPLIED_THREAD#, APPLIED_SEQ# FROM V$ARCHIVE_DEST_STATUS;

ARCHIVED_THREAD# ARCHIVED_SEQ# APPLIED_THREAD# APPLIED_SEQ#
---------------- ------------- --------------- ------------
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
1 51 1 50

可以看到備庫已經將SEQUENCE#51的日誌歸檔,已經將SEQUENCE#50的redo應用到備庫.
由於已經將SEQUENCE#51的日誌歸檔,所以SEQUENCE#51以前的資料不會丟失.

4 察看備庫已經歸檔的redo
SQL> select registrar, creator, thread#, sequence#, first_change#, next_change# from v$archived_log;

REGISTR CREATOR THREAD# SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
------- ------- ---------- ---------- ------------- ------------
SRMN SRMN 1 37 572907 573346
RFS ARCH 1 38 573346 573538
RFS ARCH 1 39 573538 573623
RFS ARCH 1 40 573623 573627
RFS ARCH 1 41 573627 574326
RFS ARCH 1 42 574326 574480

RFS ARCH 1 49 601476 601532
RFS ARCH 1 50 601532 606932
RFS ARCH 1 51 606932 607256

5 察看備庫已經應用的redo
SQL> select thread#, sequence#, first_change#, next_change# from v$log_history;

THREAD# SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- ------------- ------------
1 1 366852 368222
1 2 368222 369590
1 3 369590 371071
1 4 371071 372388
1 5 372388 376781
1 6 376781 397744
1 7 397744 407738
1 8 407738 413035
1 9 413035 413037

1 50 601532 606932
1 51 606932 607256

可以看到備庫已經將SEQUENCE#為51的歸檔檔案應用到備庫.

6 察看備庫接收,應用redo資料過程.
SQL> select message from v$dataguard_status;

MESSAGE
--------------------------------------------------------------------------------
ARC0: Archival started
ARC0: Becoming the 'no FAL' ARCH
ARC0: Becoming the 'no SRL' ARCH
ARC1: Archival started
ARC1: Becoming the heartbeat ARCH
Redo Shipping Client Connected as PUBLIC
-- Connected User is Valid
RFS[1]: Assigned to RFS process 19740
RFS[1]: Identified database type as 'physical standby'
Primary database is in MAXIMUM PERFORMANCE mode
Attempt to start background Managed Standby Recovery process

MESSAGE
--------------------------------------------------------------------------------
MRP0: Background Managed Standby Recovery process started
Managed Standby Recovery not using Real Time Apply
Clearing online redo logfile 7 /oraguard/redo1/redo_7_1.log
Clearing online redo logfile 7 complete
Media Recovery Waiting for thread 1 sequence 47
RFS[1]: No standby redo logfiles created
Redo Shipping Client Connected as PUBLIC
-- Connected User is Valid
RFS[2]: Assigned to RFS process 19746
RFS[2]: Identified database type as 'physical standby'
Primary database is in MAXIMUM PERFORMANCE mode

MESSAGE
--------------------------------------------------------------------------------
Committing creation of archivelog '/arch/1_47_552308270.arc'
Media Recovery Log /arch/1_47_552308270.arc
Media Recovery Waiting for thread 1 sequence 48
MRP0: Background Media Recovery cancelled with status 16037
MRP0: Background Media Recovery process shutdown
Managed Standby Recovery Canceled
Attempt to start background Managed Standby Recovery process
MRP0: Background Managed Standby Recovery process started
Managed Standby Recovery not using Real Time Apply
Media Recovery Waiting for thread 1 sequence 48
RFS[1]: No standby redo logfiles created

MESSAGE
--------------------------------------------------------------------------------
Committing creation of archivelog '/arch/1_48_552308270.arc'
Media Recovery Log /arch/1_48_552308270.arc
Media Recovery Waiting for thread 1 sequence 49
RFS[1]: No standby redo logfiles created
Committing creation of archivelog '/arch/1_49_552308270.arc'
Media Recovery Log /arch/1_49_552308270.arc
Media Recovery Waiting for thread 1 sequence 50
RFS[1]: No standby redo logfiles created
Committing creation of archivelog '/arch/1_50_552308270.arc'
Media Recovery Log /arch/1_50_552308270.arc
Media Recovery Waiting for thread 1 sequence 51

MESSAGE
--------------------------------------------------------------------------------
RFS[1]: No standby redo logfiles created
Committing creation of archivelog '/arch/1_51_552308270.arc'
Media Recovery Log /arch/1_51_552308270.arc
Media Recovery Waiting for thread 1 sequence 52
可以看到RFS接收到sequence#為51的歸檔檔案並存至備庫歸檔目錄/arch/1_51_552308270.arc.
Oracle自動應用檔案/arch/1_51_552308270.arc進行備庫與主庫同步
Oracle繼續等待主庫sequence 52的歸檔檔案

五 備庫歸檔目錄維護
1 找到備庫歸檔目錄
SQL> show parameter log_archive_dest_1

NAME TYPE
------------------------------------ --------------------------------
VALUE
------------------------------
log_archive_dest_1 string
LOCATION=/arch
VALID_FOR=(ALL_LOGFILES,ALL_RO
LES)
DB_UNIQUE_NAME=ora2
log_archive_dest_10 string

2 維護策略
每週2,4,7刪除已經應用的歸檔檔案
具體參見附錄二

第二部分 主庫正常切換

一 人工干預主庫正常切換

1 在主庫端檢驗資料庫可切換狀態
SQL> select switchover_status from v$database;
SWITCHOVER_STATUS
-----------------
TO STANDBY
1 row selected

SWITCHOVER_STATUS:TO STANDBY表示可以正常切換.
如果SWITCHOVER_STATUS的值為SESSIONS ACTIVE,表示當前有會話處於ACTIVE狀態

2 開始主庫正常切換
如果SWITCHOVER_STATUS的值為TO STANDBY 則:
SQL> alter database commit to switchover to physical standby;
如果SWITCHOVER_STATUS的值為SESSIONS ACTIVE 則:
SQL> alter database commit to switchover to physical standby with session shutdown;
成功執行這個命令後，主庫被修改為備庫

3 重啟先前的主庫
SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP MOUNT;

4 在備庫驗證可切換狀態
SQL> select switchover_status from v$database;
SWITCHOVER_STATUS
-----------------
TO_PRIMARY
1 row selected

5 將目標備庫轉換為主庫
如果SWITCHOVER_STATUS的值為TO STANDBY 則:
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;
如果SWITCHOVER_STATUS的值為SESSIONS ACTIVE 則:
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;
成功執行這個命令後，備庫被修改為主庫

6 重啟目標備庫
SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP;

7 先前主庫啟動日誌傳送程式
SQL> alter database recover managed standby database disconnect;

總結: 這樣主庫的一次正常切換完成.切換後的狀態,原先的主庫變為備庫,原先的備庫變為主庫.

二 透過執行指令碼實現主庫正常切換

1 主庫切換為備庫
在主庫上執行指令碼
/admin/dataGuard/switchover/primary_to_standby.sh

2 備庫切換為主庫
在備庫上執行指令碼
/admin/dataGuard/switchover/standby_to_primary.sh

指令碼1成功執行後,再執行指令碼2,不能同時執行兩個指令碼.
經過這次切換後原來的主庫變為備庫,原先的備庫變為主資料並且OPEN對應用提供服務.

3 復原最初狀態
在原備庫上執行指令碼
/admin/dataGuard/switchover/primary_to_standby.sh
成功完成後
在原主庫上執行指令碼
/admin/dataGuard/switchover/standby_to_primary.sh

第三部分 主庫災難切換
一 人工干預主庫災難切換
二 透過執行指令碼實現主庫災難切換

SQL>alter database recover managed standby database cancel;
SQL>shutdown immediate
SQL>startup mount
SQL>alter database set standby database to maximize performance;
SQL>alter database recover managed standby database finish;
-- switch
SQL>alter database commit to switchover to primary with session shutdown;
-- open
SQL>shutdown immediate
SQL>startup

附:
一 有選擇察看redo傳送與應用情況
select message from v$dataguard_status
where message_num>&message_num;

二 備庫歸檔目錄維護指令碼
在crontab 中定製每日執行removeCommand.sh即可。
流程:每日11:50PM執行removeCommand.sh
假設今日2005-04-05 則刪除04-04和04-03兩日已應用歸檔日誌.保留今日已應用歸檔日誌

[oracle@db_gurid admin]$ crontab -l
50 23 * * * sh /oraguard/admin/removeCommand.sh>>removeArch.log
##################

[oracle@db_gurid admin]$ cat removeCommand.sh
#!/bin/sh
export ORACLE_BASE=/ora10g/app
export ORACLE_HOME=$ORACLE_BASE/product/10.1.0/db_1
export ORACLE_SID=ora2

cd /oraguard/admin
$ORACLE_HOME/bin/sqlplus /nolog<conn / as sysdba
@/oraguard/admin/removeArch.sql
EOF

chmod +x /oraguard/admin/removeArch.sh
/oraguard/admin/removeArch.sh>>removeArch2.log
##################

[oracle@db_gurid admin]$ cat removeArch.sql
set feed off
set heading off
set echo off
spool removeArch.sh
select 'rm '||name from v$archived_log where applied='YES' and completion_time>trunc(sysdate-3) and completion_timespool off