Oracle 12C Active Data Guard Far Sync 配置

作者：袖梨 2022-06-29

Active Data Guard Far Sync是Oracle 12c的新功能（也称为Far Sync Standby），Far Sync功能的实现是通过在距离主库(Primary Database)相对较近的地点配置Far Sync实例，主库(Primary Database) 同步(synchronous)传输redo到Far Sync实例，然后Far Sync实例再将redo异步(asynchronous)传输到终端备库(Standby Database)。这样既可以保证零数据丢失又可以降低主库压力。Far Sync实例只有密码文件，init参数文件和控制文件，而没有数据文件。如果redo 传输采用Maximum Availability模式，我们可以在距离生产中心(Primary Database)相对较近的地点配置Far Sync实例，主库(Primary Database)同步(synchronous)传输redo到Far Sync实例，保证零数据丢失（zero data loss），同时主库和Far Sync距离较近，网络延时很小，因此对主库性能影响很小。然后Far Sync实例再将redo异步(asynchronous)发送到终端备库(Standby Database)。如果redo 传输采用Maximum Performance模式，我们可以在距离生产中心(Primary Database)相对较近的地点配置Far Sync实例，主库(Primary Database) 异步传输redo到Far Sync实例，然后Far Sync实例再负责传输redo到其他多个终端备库(Standby Database)。这样可以减少主库向多个终端备库(Standby Database)传输redo的压力（offload）。 Far Sync配置对于Data Guard 角色转换(role transitions)是透明的，即switchover/failover命令方式与12c之前相同。
1.主库配置fra
SQL> alter system set DB_RECOVERY_FILE_DEST_SIZE=200G;

System altered.

SQL> alter system set db_recovery_file_dest='/u01/app/oracle/fast_recovery_area';

System altered.
2.启用归档模式和强制日志
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.

Total System Global Area 2516582400 bytes
Fixed Size                  4585912 bytes
Variable Size             671090248 bytes
Database Buffers         1828716544 bytes
Redo Buffers               12189696 bytes
Database mounted.
SQL> alter database archivelog;

Database altered.

SQL> alter database force logging;

Database altered.

SQL> alter database open;

Database altered.
3.主机规划
192.168.137.121 ora1221   --->主库(ORCL12C)
192.168.137.122 ora1222   --->Far Sync实例(ORCL12CFS)
192.168.137.123 ora1223   --->备库(ORCL12CDG)
4.tns配置
ORCL12C =
(DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ora1221)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl12c)
    )
)

ORCL12CDG =
(DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ora1223)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl12c)
    )
)

ORCL12CFS =
(DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ora1222)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl12c)
    )
)
5.参数文件配置
--主库
db_unique_name='orcl12c'
service_names='orcl12c'
log_archive_dest_1='LOCATION=USE_DB_RECOVERY_FILE_DEST valid_for=(all_logfiles,all_roles) db_unique_name=orcl12c'
log_archive_dest_2='service=orcl12cfs lgwr sync AFFIRM MAX_FAILURE=1 ALTERNATE=LOG_ARCHIVE_DEST_3 valid_for=(online_logfiles,primary_role) db_unique_name=orcl12cfs'
LOG_ARCHIVE_DEST_3='SERVICE=orcl12cdg lgwr ASYNC ALTERNATE=LOG_ARCHIVE_DEST_2 VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=orcl12cdg'
LOG_ARCHIVE_DEST_STATE_3=ALTERNATE
log_archive_config='dg_config=(orcl12c,orcl12cdg,orcl12cfs)'
standby_file_management=auto
db_file_name_convert='/u01/app/oracle/oradata/orcl12c/','/u01/app/oracle/oradata/orcl12c/'
log_file_name_convert='/u01/app/oracle/oradata/orcl12c/','/u01/app/oracle/oradata/orcl12c/'
fal_server='orcl12cdg','orcl12cfs'

--Far Sync实例
db_unique_name='orcl12cfs'
service_names='orcl12c'
log_archive_dest_1='LOCATION=USE_DB_RECOVERY_FILE_DEST valid_for=(all_logfiles,all_roles) db_unique_name=orcl12cfs'
log_archive_dest_2='service=orcl12cdg lgwr async valid_for=(STANDBY_LOGFILES,STANDBY_ROLE) db_unique_name=orcl12cdg'
log_archive_config='dg_config=(orcl12c,orcl12cdg,orcl12cfs)'
standby_file_management=manual
fal_server='orcl12c'

--备库
db_unique_name='orcl12cdg'
service_names='orcl12c'
log_archive_dest_1='LOCATION=USE_DB_RECOVERY_FILE_DEST valid_for=(all_logfiles,all_roles) db_unique_name=orcl12cdg'
log_archive_dest_2='service=orcl12c lgwr async   valid_for=(online_logfiles,primary_role) db_unique_name=orcl12c'
log_archive_config='dg_config=(orcl12c,orcl12cdg,orcl12cfs)'
standby_file_management=auto
db_file_name_convert='/u01/app/oracle/oradata/orcl12c/','/u01/app/oracle/oradata/orcl12c/'
log_file_name_convert='/u01/app/oracle/oradata/orcl12c/','/u01/app/oracle/oradata/orcl12c/'
fal_server='orcl12c','orcl12cfs'
6.密码文件
拷贝主库的密码文件到Far Sync实例和备库$ORACLE_HOME/dbs下(如果是win在%ORACLE_HOME%/database中)

7.创建Far Sync实例
创建和参数文件匹配的fra,adump目录
--主库
ALTER DATABASE CREATE FAR SYNC INSTANCE CONTROLFILE AS '/tmp/controlfs01.ctl';
拷贝到Far Sync实例对应的控制文件位置

--Far Sync实例
startup pfile='/tmp/pfile' mount

ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 10 '/u01/app/oracle/oradata/orcl12c/std_redo10.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 11 '/u01/app/oracle/oradata/orcl12c/std_redo11.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 12 '/u01/app/oracle/oradata/orcl12c/std_redo12.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 13 '/u01/app/oracle/oradata/orcl12c/std_redo13.log' size 50m reuse;

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
8.创建备库
创建和参数文件匹配的fra,adump目录
--主库备份（传输至备库）
backup database format '/tmp/ora12c_%U';

--主库创建standby ctl（传输至备库和备库参数文件路径一致）
alter database create standby controlfile as '/tmp/controlst.ctl';

--启动备库至mount
startup pfile='/tmp/pfile' mount;

--备库注册备份
catalog start with '/tmp/xifenfei/';

--备库还原数据文件并恢复
restore database;
recover database;

--增加standby redo
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 10 '/u01/app/oracle/oradata/orcl12c/std_redo10.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 11 '/u01/app/oracle/oradata/orcl12c/std_redo11.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 12 '/u01/app/oracle/oradata/orcl12c/std_redo12.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 13 '/u01/app/oracle/oradata/orcl12c/std_redo13.log' size 50m reuse;

--备库开启mrp进程
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;

--主库增加standby redo
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 10 '/u01/app/oracle/oradata/orcl12c/std_redo10.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 11 '/u01/app/oracle/oradata/orcl12c/std_redo11.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 12 '/u01/app/oracle/oradata/orcl12c/std_redo12.log' size 50m reuse;
ALTER DATABASE ADD STANDBY LOGFILE thread 1 GROUP 13 '/u01/app/oracle/oradata/orcl12c/std_redo13.log' size 50m reuse;
9.配置结果
SQL> select * from V$DATAGUARD_CONFIG;

DB_UNIQUE_NAME                 PARENT_DBUN                    DEST_ROLE         CURRENT_SCN     CON_ID
------------------------------ ------------------------------ ----------------- ----------- ----------
orcl12c                        NONE                           PRIMARY DATABASE      1950551          0
orcl12cfs                      orcl12c                        FAR SYNC INSTANCE     1950390          0
orcl12cdg                      orcl12cfs                      PHYSICAL STANDBY      1950390          0

SQL> select group#, status, thread#, sequence#, first_change#, next_change# from v$standby_log;

    GROUP# STATUS        THREAD# SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- ---------- ---------- ------------- ------------
        10 ACTIVE              1         27       1863140
        11 UNASSIGNED          1          0
        12 UNASSIGNED          1          0
        13 UNASSIGNED          1          0

SQL> select PROTECTION_MODE,PROTECTION_LEVEL from v$database;

PROTECTION_MODE      PROTECTION_LEVEL
-------------------- --------------------
MAXIMUM PERFORMANCE MAXIMUM PERFORMANCE
10.调整保护级别
从MAXIMUM PERFORMANCE调整为MAXIMUM AVAILABILITY
--主库
SQL> startup mount;
ORACLE instance started.

Total System Global Area 2516582400 bytes
Fixed Size                  4585912 bytes
Variable Size             671090248 bytes
Database Buffers         1828716544 bytes
Redo Buffers               12189696 bytes
Database mounted.
SQL> alter database set standby database to maximize availability;

Database altered.

SQL> select PROTECTION_MODE,PROTECTION_LEVEL from v$database;

PROTECTION_MODE      PROTECTION_LEVEL
-------------------- --------------------
MAXIMUM AVAILABILITY UNPROTECTED

SQL> alter database open;

Database altered.

SQL> select PROTECTION_MODE,PROTECTION_LEVEL from v$database;

PROTECTION_MODE      PROTECTION_LEVEL
-------------------- --------------------
MAXIMUM AVAILABILITY MAXIMUM AVAILABILITY

--Far Sync实例
SQL> select PROTECTION_MODE,PROTECTION_LEVEL from v$database;

PROTECTION_MODE      PROTECTION_LEVEL
-------------------- --------------------
MAXIMUM AVAILABILITY MAXIMUM AVAILABILITY

--备库
SQL> select PROTECTION_MODE,PROTECTION_LEVEL from v$database;

PROTECTION_MODE      PROTECTION_LEVEL
-------------------- --------------------
MAXIMUM AVAILABILITY RESYNCHRONIZATION