snapshot standby database

快照备库接收和归档主库发送来的redo，但是不会应用；切换成physical standby之后会自动开启redo apply。
快照standby不可以参加主备切换；在最大保护性模式下，如果只有一个备库，则不可以将备库转成snapshot standby。

 

将Physical Standby Database转换成Snapshot Standby Database

1.停止redo apply

?

1	SQL> alter database recover managed standby database cancel;

2.确保数据是mounted状态，而不是open状态

?

1 2 3 4 5 6 7

SQL> select open_mode,database_role from v$database;   OPEN_MODE            DATABASE_ROLE -------------------- ---------------- MOUNTED              PHYSICAL STANDBY   SQL>

3.确认已经创建好fast recovery area(不需要对数据库开启闪回)

?

1 2 3 4 5 6 7

SQL> show parameter db_recovery_file   NAME                                 TYPE        VALUE ------------------------------------ ----------- ------------------------------ db_recovery_file_dest                string      /s01/app/oracle/flash db_recovery_file_dest_size           big integer 4G SQL>

4.执行转换

?

1 2 3 4 5 6 7 8 9 10 11

SQL> alter database convert to snapshot standby ;   Database altered.   SQL> select open_mode,database_role from v$database;   OPEN_MODE            DATABASE_ROLE -------------------- ---------------- MOUNTED              SNAPSHOT STANDBY   SQL>

5.将数据打开

?

1 2 3 4 5 6 7 8 9 10 11 12

SQL> alter database open;   Database altered.   #打开模式已经改变，但是角色不变 SQL> select open_mode,database_role from v$database;   OPEN_MODE            DATABASE_ROLE -------------------- ---------------- READ WRITE           SNAPSHOT STANDBY   SQL>

 

 

将Snapshot Standby Database切换成Physical Standby Database

1.如果是RAC环境，要先关掉所有实例
2.将数据库启动到mount状态
3.执行切换

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

SQL> select open_mode,database_role from v$database;   OPEN_MODE            DATABASE_ROLE -------------------- ---------------- MOUNTED              SNAPSHOT STANDBY   SQL> alter database convert to physical standby;   Database altered.   #转换命令结束后，数据库会自动被dismounted，需要关闭重启数据库。 SQL> select open_mode,database_role from v$database; select open_mode,database_role from v$database                                     * ERROR at line 1: ORA-01507: database not mounted     SQL> startup mount ORA-01081: cannot start already-running ORACLE - shut it down first SQL> shutdown immediate ORA-01507: database not mounted     ORACLE instance shut down. SQL> startup mount ORACLE instance started.   Total System Global Area  430075904 bytes Fixed Size                  2253944 bytes Variable Size             184552328 bytes Database Buffers          239075328 bytes Redo Buffers                4194304 bytes Database mounted. SQL>