Oracle：Data Guard

 

 

是什么：

          pirmary/production database + physical standby database(redo) + logical standby database(sql) + 快照

          物理备份就是standby库的物理文件还有逻辑结构都跟主库完全一致（99.9%），会执行传递过来的日志里的所有动作。
逻辑备份则是将传递过来的日志里面的sql语句提取出来进行执行，保证数据库逻辑上的一致，也就是表，表空间，视图这些跟主库是一致的，但是物理文件则不一定，比如你主表的默认表空间可能之前定义的是在Auser，但你备库的则是在默认表空间，这样数据是一样的，只是存放地点不一样。

干什么的：

         --data protection(receive and apply redo)

         --reporting(read only access),backup,query 

         --upgrade  

 

特点：

       三种服务 services:
            --redo transport services
            --apply services
            --role transtions (Switchover + Failover)

 

       三种保护模式

       --maximum protection
       --        avaliability
       --        performance 

 

1.最大保护模式
1）这种模式提供了最高级别的数据保护能力；
2）要求至少一个物理备库收到重做日志后，主库的事务才能够提交；
3）主库找不到合适的备库写入时，主库会自动关闭，防止未受保护的数据出现；
4）优点：该模式可以保证备库没有数据丢失；
5）缺点：主库的自动关闭会影响到主库的可用性，同时需要备库恢复后才能提交，对网络等客观条件要求非常的高，主库的性能会因此受到非常大的冲击。

2.最大可用性模式
1）该模式提供了仅次于“最大保护模式”的数据保护能力；
2）要求至少一个物理备库收到重做日志后，主库的事务才能够提交；
3）主库找不到合适的备库写入时，主库不会关闭，而是临时降低到“最大性能模式”模式，直到问题得到处理；
4）优点：该模式可以在没有问题出现的情况下，保证备库没有数据丢失，是一种折中的方法；
5）缺点：在正常运行的过程中缺点是主库的性能受到诸多因素的影响。

3.最大性能模式
1）该模式是默认模式，可以保证主数据库的最高可用性；
2）保证主库运行过程中不受备库的影响，主库事务正常提交，不因备库的任何问题影响到主库的运行；
4）优点：避免了备库对主数据库的性能和可用性影响；
5）缺点：如果与主库提交的事务相关的恢复数据没有发送到备库，这些事务数据将被丢失，不能保证数据无损失；

The primary database is open and active. The standby databases are either in recovery mode or open in read-only mode, but not both

  三种管理工具：

        --sqlplus 
        --dgmgrl
        --oem(给用户和领导看)

 

 小结:
    在部署Oracle Dataguard时，需要充分考虑三种保护模式下对数据和性能的影响，以便趋利避害。具体环境具体分析，每一种数据保护模式都有其应用场合。默认的最大性能模式较常见，运行在该模式下的系统需要时刻注意备库是否有日志丢失，通常可以考虑“一主带多备”（一套主库对应多个备库）的方法来保证日志的完整性。

      在实际环境中，主备库之间的切换动作一般都需要非常慎重，因此，多以手工方式来完成。

 

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

 

----标准DataGuard参数设置------------------------------
alter system set log_archive_dest_2='SERVICE=ta_std REOPEN=300  VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLES) db_unique_name=ta_std';
alter system set fal_server='ta_std';
alter system set fal_client='ta';

alter system set fal_server='ta';
alter system set fal_client='ta_std';

----利用ssh tunnel的DataGuard参数设置------------------------------
alter system set log_archive_dest_2 = 'SERVICE=ta_ssh NOREOPEN VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLES) db_unique_name=ta_std alternate=log_archive_dest_3';
alter system set log_archive_dest_state_2= enable;
--注意：log_archive_dest_2需要设置noreopen或者reopen=0属性，否则无法迅速切换到备用路径。

alter system set log_archive_dest_3 = 'SERVICE=ta_std REOPEN=300 VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLES) db_unique_name=ta_std';
alter system set log_archive_dest_state_3=alternate;
--注意：当归档目标log_archive_dest_2不能正常归档时，数据库切换归档目标到log_archive_dest_3，即使log_archive_dest_2归档目标恢复正常，也不会再自动切换回去，需要手工重新修改路径状态参数：
--alter system set log_archive_dest_state_2= enable;
--alter system set log_archive_dest_state_3= alternate;

alter system set fal_server = 'ta_ssh';
alter system set fal_client = 'ta';

测试
tnsping ta     tnsing ta_std     tnsing ta_ssh

 

 

------------------------------------------------------
p170a:    ssh -L 15210:p170b:1521 -C -N p170b
p170b:    ssh -L 15210:p170a:1521 -C -N p170a

redhat1:    ssh -L 15210:redhat2:1521 -C -N redhat2
redhat2:    ssh -L 15210:redhat1:1521 -C -N redhat1

----DataGuard 中注册日志文件------------------------------
alter database register OR replace logfile '/data/arch_ta/1_515_673519034.dbf';

注册日志文件
catalog archivelog '....';

ALTER SESSION SET nls_date_format = 'YYYY-MM-DD HH24:MI:SS';
SELECT TIMESTAMP,MESSAGE FROM V$DATAGUARD_STATUS;

SELECT * FROM (SELECT THREAD#,SEQUENCE#,FIRST_CHANGE#,NEXT_CHANGE#,APPLIED FROM V$ARCHIVED_LOG ORDER BY FIRST_CHANGE# DESC) WHERE ROWNUM<20;

一、PRIMARY DATABASE

1、设置DB FORCE_LOGGING为YES
SELECT FORCE_LOGGING FROM V$DATABASE;
ALTER DATABASE FORCE LOGGING;
ALTER DATABASE NO FORCE LOGGING;

2、设置保护模式
SELECT OPEN_MODE,DATABASE_ROLE,SWITCHOVER_STATUS,PROTECTION_MODE, PROTECTION_LEVEL FROM V$DATABASE;
ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PROTECTION;
ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE AVAILABILITY;
ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE;

3、设置归档目标
ALTER SYSTEM SET log_archive_dest_1='location=/app/oracle/arch';
ALTER SYSTEM set LOG_ARCHIVE_DEST_2='SERVICE=ta_std REOPEN=300  VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLES)';
ALTER SYSTEM SET log_archive_dest_state_1=enable;
ALTER SYSTEM SET log_archive_dest_state_2=defer;

ALTER SYSTEM SET fal_server=ta_std;
ALTER SYSTEM SET fal_client=fmp;

ALTER SYSTEM set DB_FILE_NAME_CONVERT='fmpdb','fmpdb' SCOPE=SPFILE;
ALTER SYSTEM set LOG_FILE_NAME_CONVERT='fmpdb','fmpdb' SCOPE=SPFILE;
ALTER SYSTEM SET standby_file_management=auto;

二、STANDBY DATABASE

1、建目录结构
D:\oracle\product\10.2.0\admin
D:\oracle\product\10.2.0\flash_recovery_area
D:\oracle\product\10.2.0\oradata\fmpdb
D:\oracle\product\10.2.0\oradata\fmpdbarch

2、copy
D:\oracle\product\10.2.0\db_1\database\PWDfmpdb.ora
D:\oracle\product\10.2.0\db_1\database\SPFILEFMPDB.ORA
D:\oracle\product\10.2.0\db_1\NETWORK\ADMIN\listener.ora  需修改IP
D:\oracle\product\10.2.0\db_1\NETWORK\ADMIN\tnsnames.ora

C:\> ORADIM -NEW -sid fmpdb
C:\> orapwd file=D:\oracle\product\10.2.0\db_1\database\PWDfmpdb.ora password=oracle force=y
--password必须与PRIMARY保持一致

starup nomount
ALTER SYSTEM SET log_archive_dest_1='location=D:\oracle\product\10.2.0\oradata\fmpdbarch';
ALTER SYSTEM set LOG_ARCHIVE_DEST_2='SERVICE= REOPEN=300 VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLES)';
--ALTER SYSTEM reset LOG_ARCHIVE_DEST_2 scope=spfile sid='*';
ALTER SYSTEM SET log_archive_dest_state_1=enable;
ALTER SYSTEM SET log_archive_dest_state_1=defer;

ALTER SYSTEM SET fal_server=fmp;
ALTER SYSTEM SET fal_client=fmp_std;

三、PRIMARY DATABASE

RMAN 备份：
rman target /
crosscheck backup;
delete noprompt expired backup;
crosscheck archivelog all;
delete noprompt expired archivelog all;

BACKUP format 'D:\oracle\product\10.2.0\oradata\backup\%d_STBY_%T_%s_%p' current controlfile for standby;
BACKUP format 'D:\oracle\product\10.2.0\oradata\backup\%d_FULL_%T_%s_%p' database MAXSETSIZE 2G;
SQL 'alter system archive log current';
BACKUP format 'D:\oracle\product\10.2.0\oradata\backup\%d_ARCH_%T_%s_%p' archivelog all MAXSETSIZE 2G;
exit;

四、STANDBY DATABASE
1、copy 主D:\oracle\product\10.2.0\oradata\backup\*.*至备
2、
RMAN target sys/oracle@fmp
connect auxiliary sys/oracle@fmp_std
duplicate target database for standby nofilenamecheck;
 [dorecover];

五、PRIMARY DATABASE
ALTER SYSTEM SET log_archive_dest_state_2=enable;

六、STANDBY DATABASE
startup mount
ALTER SYSTEM SET log_archive_dest_state_2=enable;

--启动了MRP0进程(Managed Standby Recovery)
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
ALTER DATABASE OPEN;

七、检查
--查询尚未APPLIED的archived log(STANDBY端)
SELECT * FROM (SELECT THREAD#,SEQUENCE#,FIRST_CHANGE#,NEXT_CHANGE#,APPLIED FROM V$ARCHIVED_LOG ORDER BY FIRST_CHANGE# DESC) WHERE ROWNUM<20;

--察看从数据库已经归档的redo
SELECT REGISTRAR,CREATOR,THREAD#,SEQUENCE#,APPLIED,FIRST_CHANGE#,NEXT_CHANGE# FROM V$ARCHIVED_LOG;

--察看从数据库已经应用的redo
SELECT THREAD#, SEQUENCE#, FIRST_CHANGE#, NEXT_CHANGE# FROM V$LOG_HISTORY;

--DATAGUARD 状态
ALTER SESSION SET nls_date_format = 'YYYY-MM-DD HH24:MI:SS';
SELECT TIMESTAMP,MESSAGE FROM V$DATAGUARD_STATUS;

--从数据库端察看RFS(Remote File Service)接收日志情况和MRP应用日志同步主数据库情况
COL STATUS FORMAT A15
SELECT PROCESS,STATUS,THREAD#,SEQUENCE#,BLOCK#,BLOCKS FROM V$MANAGED_STANDBY;

--察看从数据库是否和主数据库同步
COL DEST_NAME FORMAT A20
SELECT DEST_NAME,ARCHIVED_THREAD#, ARCHIVED_SEQ#, APPLIED_THREAD#, APPLIED_SEQ# FROM V$ARCHIVE_DEST_STATUS;

col DESTINATION format a50
SELECT DEST_NAME,DESTINATION, STATUS, ARCHIVED_THREAD#, ARCHIVED_SEQ# FROM V$ARCHIVE_DEST_STATUS WHERE STATUS <> 'DEFERRED' AND STATUS <> 'INACTIVE';

--GAP
SELECT * FROM V$ARCHIVE_GAP;

第二部分 主数据库正常切换

一 人工干预主数据库正常切换

1 在主数据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 开始主数据库正常切换 IP:172.16.75.35
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，主数据库被修改为从数据库

3 重启先前的主数据库
SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP MOUNT;

4 在从数据库端验证可切换状态 IP:172.16.75.30
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
-----------------
TO_PRIMARY
1 row selected

5 将目标从数据库转换为主数据库 IP:172.16.75.30
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，从数据库被修改为主数据库

6 重启目标从数据库
SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP;

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

 

============================================================================
--ALTER SYSTEM set log_archive_config='DG_CONFIG=(testdb,testdb2)';

ALTER DATABASE CREATE STANDBY CONTROLFILE AS 'D:\oracle\product\10.2.0\oradata\boston\CONTROL01.CTL';

--启动了MRP0进程(Managed Standby Recovery)
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
ALTER DATABASE OPEN;

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;

SET PAGESIZE 200
SELECT * FROM V$PROCESS;
SELECT * FROM V$BGPROCESS WHERE PADDR<>'00';

SELECT USERNAME,TERMINAL,PROGRAM FROM V$PROCESS;
SELECT * FROM V$BGPROCESS WHERE PADDR<>'00';
COL USERNAME FORMAT A15
COL MACHINE FORMAT A30
SELECT USERNAME,MACHINE,TERMINAL,PROGRAM FROM V$SESSION;

 

 

-------

rman nocatalog target sys/oracle@ta
run {
ALLOCATE CHANNEL c1 DEVICE TYPE DISK CONNECT 'sys/oracle@ta1' format '/app/oracle/backup/rac1_%U';
ALLOCATE CHANNEL c2 DEVICE TYPE DISK CONNECT 'sys/oracle@ta2' format '/app/oracle/backup/rac2_%U';
sql 'alter system archive log current';
backup filesperset 3 archivelog all delete all input;
release channel c1;
release channel c2;
}

rman nocatalog target sys/oracle@ta
run {
ALLOCATE CHANNEL c1 DEVICE TYPE DISK CONNECT 'sys/oracle@ta1';
ALLOCATE CHANNEL c2 DEVICE TYPE DISK CONNECT 'sys/oracle@ta2';
BACKUP FORMAT '/app/oracle/backup/%t_%U' DATABASE PLUS ARCHIVELOG;
BACKUP FORMAT '/app/oracle/backup/%t_%U' CURRENT CONTROLFILE FOR STANDBY;
release channel c1;
release channel c2;
}

-----RAC环境下，交叉验证-----------------------------------------
allocate channel for maintenance device type DISK connect 'sys/oracle@ora921';
allocate channel for maintenance device type DISK connect 'sys/oracle@ora922';
crosscheck archivelog all;
delete noprompt expired archivelog all;
release channel;

crosscheck backup;
delete noprompt expired backup;
delete noprompt obsolete;
release channel;
-------------------------------------------------------------------------

RMAN>
catalog archivelog '/arch/ora92/2_1.dbf';
list archivelog all;

scp -p -r oracle@192.168.192.71:/app/oracle/backup /app/oracle
scp -p -r oracle@192.168.192.72:/app/oracle/backup /app/oracle

orapwd file=/app/oracle/product/10.2.0/db_1/dbs/orapwta password=oracle force=y

ALTER SYSTEM set DB_FILE_NAME_CONVERT='ta','ta' SCOPE=SPFILE;
ALTER SYSTEM set LOG_FILE_NAME_CONVERT='ta','ta' SCOPE=SPFILE;

rman target sys/oracle@ta
connect auxiliary sys/oracle@ta_std
duplicate target database for standby nofilenamecheck;

--primary
ALTER SYSTEM SET log_archive_config='dg_config=(ta,ta_std)' sid='*';
ALTER SYSTEM SET log_archive_dest_1='location=/app/oracle/arch' sid='*';
ALTER SYSTEM set LOG_ARCHIVE_DEST_2='SERVICE=ta_std REOPEN=300  VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLES) db_unique_name=ta_std' sid='*';
ALTER SYSTEM SET log_archive_dest_state_1=enable sid='*';
ALTER SYSTEM SET log_archive_dest_state_2=defer sid='*';
ALTER SYSTEM SET standby_file_management=auto sid='*'

--standby
ALTER SYSTEM SET log_archive_config='dg_config=(ta,ta_std)';
ALTER SYSTEM SET standby_file_management=auto;
ALTER SYSTEM SET fal_server='ta1','ta2';
ALTER SYSTEM SET fal_client='ta_std';

ALTER SYSTEM SET log_archive_dest_state_2=enable sid='*';

ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;
recover managed standby database finish;

 

通过故障切换实现角色转换
1、查询备用数据中v$archive_gap视图来定位备用数据库中的日志缺失。
2、在备用数据库中通过下面的命令对归档日志进行注册
   alter database register physical logfile '......';
3、alter database recover managed standby database finish;
   alter database recover managed standby database finish skip standby logfile;
4、alter database commit to switchover to primary;
5、shutdown immediate;
   startup;

 

fmpdb =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.20.1)(PORT = 1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.20.2)(PORT = 1521))
      (LOAD_BALANCE = yes)
    )
    (CONNECT_DAfmpdb =
      (SERVICE_NAME = fmpdb)
       (FAILOVER_MODE =
        (TYPE = SELECT)
        (METHOD = BASIC)
        (RETRIES = 180)
        (DELAY = 5)
      )
    )
  )

fmpdb1 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.20.1)(PORT = 1521))
    )
    (CONNECT_DAfmpdb =
      (SERVICE_NAME = fmpdb)
    )
  )

fmpdb2 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.20.2)(PORT = 1521))
    )
    (CONNECT_DAfmpdb =
      (SERVICE_NAME = fmpdb)
    )
  )

fmpdb_std =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 172.18.0.11)(PORT = 1521))
    (CONNECT_DAfmpdb =
      (SERVER = DEDICATED)
      (SERVICE_NAME = fmpdb)
    )
  )

-------------------------------------------------------------------------------
http://hi.baidu.com/dbaeyes/blog/item/740c3bfb3e0d5361034f568e.html

standby 管理和维护2008年07月13日 星期日 00:31管理：

查询库状态：
SQL> select name,SWITCHOVER_STATUS,open_mode,PROTECTION_MODE,DATABASE_ROLE
          from v$database;

验证archive log是否接收和 applied.
SQL> alter session set nls_datE_format='YYYY-MM-DD HH24:MI:SS';

select SEQUENCE#,DEST_ID,ARCHIVED,APPLIED,DELETED,
STATUS,FIRST_TIME from v$archived_log order by SEQUENCE#;

启动到管理模式:
SQL> shutdown immediate;
SQL> startup nomount
SQL> alter database mount standby database
SQL> recover managed standby database disconnect from session;
----------

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

10g以后，采用联机日志的传递传递方式，
SQL> recover managed standby database using current logfile disconnect from session;

启动到只读模式：
SQL> shutdown immediate;
SQL> startup nomount
SQL> alter database mount standby database
SQL> alter databae open read only;

在管理模式恢复到只读模式：
SQL> recover managed standby database cancel;
SQL> alter database open read only

在只读模式可以给数据库添加临时数据文件（在rman备份是没有备份的），想让standby提供只读服务或者切换成主库，最好先增加链式文件
SQL> alter tablespace temp add tempfile 'C:\oracle\product\10.2.0\oradata\dgtest\temp02.dbf' size 100m;

只读模式到管理模式
SQL> recover managed standby database disconnect from session;

在备库进行备份
1.停止应用程序，跳转到 read only模式，同坐backup database命令来备份数据库，这样数据库处于一致性模式
2. 备份完成后，备份控制文件
SQL> ALTER DATABASE BACKUP CONTROLFILE TO 'FILE NAME';

主备切换

正常切换 (switchover)
切换准备: 准备参数文件，平时应该备好，注意参数 fal_server，fal_client

先确认能否转换：
SELECT SWITCHOVER_STATUS FROM V$DATABASE;

主 -> 备
$lsnrclt stop
杀光进程或者重启数据库
SQL> alter database commit to switchover to physical standby with session shutdown;

SQL> shutdown immediate;
SQL> startup nomount pfile ='';
SQL> alter database mount standby database;
SQL> recover managed standby database disconnect;

备 -> 主
SQL> alter database commit to switchover to primary with session shutdown;
SQL> shutdown immediate
SQL> startup pfile =''

如果考虑在主备库来回切换，要保证数据库版本一致，参数compatible一致

失败切换 (Failover)
主服务器不能使用情况下

在备库
SQL> recover managed standby database cancel;

--如果在备用库上有备用库日志文件，参考命令
SQL> alter database recover managed standby database finish; -- [force|wait|nowait] 10g or later
--没有备库日志文件[10gR2之前]
SQL> alter database recover managed standby database finish skip standby logfile;

--切换备库到主库
SQL> alter database commit to switchover to primary;
-- open
SQL> shutdown immediate;
SQL> startup pfile=''

如果还有为传递的归档日志或者主库的联机日志
SQL>alter database register logfile 'c:\...'
SQL>recover standby database;

强行切换（激活）
激活备用服务器，在重启数据库时，备库会resetlog。
SQL>alter system archive log current;
SQL>recover managed standby database cancel;
SQL>alter database activate standby database;
SQL>shutdown immediate;
SQL>startup pfile=''

-----
apply 主库redolog并强制切换
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
--选定redolog恢复
SQL> recover standby database until cancel;

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
/u01/oradata/dgtest/redo02.log
Log applied.
Media recovery complete.

recovery 完成之后就要failover了。

SQL>alter database activate standby database;
SQL>shutdown immediate;
SQL>startup pfile=''
-- http://hi.baidu.com/wa0362/blog/item/33e52912a91eadcbc2fd78b9.html
-- http://zf_wu.itpub.net/

-- 参考来源： 《oracle高可用环境》

--http://www.oracleblog.cn/study-note/reduce-the-data-loss-of-data-guard-when-failover/

相关视图

v$archive_dest
v$archive_dest_status
v$log_history
v$archvied_log
v$managed_standby
v$archive_gap

-- EOF --

http://oracle.chinaitlab.com/serial/740174.html

激活备库到read/write状态
SQL> alter database activate standby database;
数据库已更改。
SQL> alter database open;
数据库已更改。

转换成备库
SQL> alter database convert to physical standby;
数据库已更改。

-- EOF --

 

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高级复制（Advanced Replication）、流复制（Streams Replication）、备库（Dataguard）区别：

http://sky13and23.blog.163.com/blog/static/286930842009118685924/

 

 

DataGuard逻辑备库之原理与配置：

http://justdba.blogbus.com/logs/66233510.html