DataGuard日常维护方式

本篇内容介绍了“DataGuard日常维护方式”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！

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第一部分 日常维护

一 正确打开主库和备库
1 主库:
SQL> STARTUP MOUNT;
SQL> ALTER DATABASE ARCHIVELOG;
SQL> ALTER DATABASE OPEN;

2 备库:
SQL> STARTUP MOUNT;

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
 

二 正确关闭顺序
1 备库:
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
SQL>SHUTDOWN IMMEDIATE;

2 主库
SQL>SHUTDOWN IMMEDIATE;

三 备库Read-Only模式打开
当前主库正常OPEN状态
备库处于日志传送状态.

1 在备库停止日志传送
SQL> recover managed standby database cancel;

2 备库Read-only模式打开
SQL> alter database open read only;

3 备库回到日志传送模式
SQL> recover managed standby database disconnect from session;
Media recovery complete.
SQL> select status from v$instance;

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

四 日志传送状态监控

1 主库察看当前日志状况
SQL> select sequence#,status from v$log;

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

2 备库察看RFS(Remote File Service)接收日志情况和MRP应用日志同步主库情况
SQL> SELECT PROCESS, STATUS, THREAD#, SEQUENCE#, BLOCK#, BLOCKS
 2  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
可以看到备库MPR0正等待SEQUENCE#为52的redo.

3 察看备库是否和主库同步
SQL> SELECT ARCHIVED_THREAD#, ARCHIVED_SEQ#, APPLIED_THREAD#, APPLIED_SEQ#
 2  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

可以看到备库已经将SEQUENCE#51的日志归档,已经将SEQUENCE#50的redo应用到备库.
由于已经将SEQUENCE#51的日志归档,所以SEQUENCE#51以前的数据不会丢失.

4 察看备库已经归档的redo
SQL> SELECT REGISTRAR, CREATOR, THREAD#, SEQUENCE#, FIRST_CHANGE#,
 2  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         43        574480       590971
RFS     ARCH             1         44        590971       593948
RFS     FGRD             1         45        593948       595131
RFS     FGRD             1         46        595131       595471
FGRD    FGRD             1         46        595131       595471

REGISTR CREATOR    THREAD#  SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
------- ------- ---------- ---------- ------------- ------------
RFS     ARCH             1         47        595471       595731
RFS     ARCH             1         48        595731       601476
RFS     ARCH             1         49        601476       601532
RFS     ARCH             1         50        601532       606932
RFS     ARCH             1         51        606932       607256

5 察看备库已经应用的redo
SQL> SELECT THREAD#, SEQUENCE#, FIRST_CHANGE#, NEXT_CHANGE#
 2  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         10        413037       413039
        1         11        413039       413098

THREAD#  SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- ------------- ------------
        1         12        413098       428161
        1         13        428161       444373
        1         14        444373       457815
        1         15        457815       463016
        1         16        463016       476931
        1         17        476931       492919
        1         18        492919       505086
        1         19        505086       520683
        1         20        520683       530241
        1         21        530241       545619
        1         22        545619       549203

THREAD#  SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- ------------- ------------
        1         23        549203       552403
        1         24        552403       553230
        1         25        553230       553398
        1         26        553398       553695
        1         27        553695       554327
        1         28        554327       557569
        1         29        557569       561279
        1         30        561279       561385
        1         31        561385       566069
        1         32        566069       566825
        1         33        566825       570683

THREAD#  SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- ------------- ------------
        1         34        570683       571627
        1         35        571627       571867
        1         36        571867       572907
        1         37        572907       573346
        1         38        573346       573538
        1         39        573538       573623
        1         40        573623       573627
        1         41        573627       574326
        1         42        574326       574480
        1         43        574480       590971
        1         44        590971       593948

THREAD#  SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- ------------- ------------
        1         45        593948       595131
        1         46        595131       595471
        1         47        595471       595731
        1         48        595731       601476
        1         49        601476       601532
        1         50        601532       606932
        1         51        606932       607256

可以看到备库已经将SEQUENCE#为51的归档文件应用到备库.

6 察看备库接收,应用redo数据过程.
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#为51的归档文件并存至备库归档目录/arch/1_51_552308270.arc.
Oracle自动应用文件/arch/1_51_552308270.arc进行备库与主库同步
Oracle继续等待主库sequence 52的归档文件

五 备库归档目录维护
1 找到备库归档目录
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 维护策略
每周2,4,7删除已经应用的归档文件
具体参见附录二

第二部分 主库正常切换

一 人工干预主库正常切换

1 在主库端检验数据库可切换状态
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
-----------------
TO STANDBY
1 row selected

SWITCHOVER_STATUS:TO STANDBY表示可以正常切换.
如果SWITCHOVER_STATUS的值为SESSIONS ACTIVE,表示当前有会话处于ACTIVE状态

2 开始主库正常切换
如果SWITCHOVER_STATUS的值为TO STANDBY 则:
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY;
如果SWITCHOVER_STATUS的值为SESSIONS ACTIVE 则:
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN;
成功运行这个命令后，主库被修改为备库

3 重启先前的主库
SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP MOUNT;

4 在备库验证可切换状态
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
-----------------
TO_PRIMARY
1 row selected

5 将目标备库转换为主库
如果SWITCHOVER_STATUS的值为TO STANDBY 则:
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;
如果SWITCHOVER_STATUS的值为SESSIONS ACTIVE 则:
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;
成功运行这个命令后，备库被修改为主库

6 重启目标备库
SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP;

7 先前主库启动日志传送进程
SQL> alter database recover managed standby database disconnect;

总结: 这样主库的一次正常切换完成.切换后的状态,原先的主库变为备库,原先的备库变为主库.

二 通过运行脚本实现主库正常切换

1 主库切换为备库
在主库上运行脚本
/admin/dataGuard/switchover/primary_to_standby.sh

2 备库切换为主库
在备库上运行脚本
/admin/dataGuard/switchover/standby_to_primary.sh

脚本1成功运行后,再运行脚本2,不能同时运行两个脚本.
经过这次切换后原来的主库变为备库,原先的备库变为主数据并且OPEN对应用提供服务.

3 复原最初状态
在原备库上运行脚本
/admin/dataGuard/switchover/primary_to_standby.sh
成功完成后
在原主库上运行脚本
/admin/dataGuard/switchover/standby_to_primary.sh

第三部分 主库灾难切换
一 人工干预主库灾难切换
二 通过运行脚本实现主库灾难切换

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 有选择察看redo传送与应用情况
select message from v$dataguard_status
where message_num>&message_num;

二 备库归档目录维护脚本
在crontab 中定制每日执行removeCommand.sh即可。
流程:每日11:50PM执行removeCommand.sh
假设今日2005-04-05 则删除04-04和04-03两日已应用归档日志.保留今日已应用归档日志

[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>>removeArch3.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

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