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标题：dataguard配合flashback实现主备任意切换(failover和switchover)
作者：惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]
有客户使用本地和公有云通过vpn搭建数据库容灾,其中有一个需求,当本地环境出现问题云端容灾库接管业务,当本地环境恢复之后,本地继续做为主库,云端作为备库.我这里使用oracle dataguard结合flashback模拟实现客户需求(也可以在failover之后通过重新搭建dg实现类似需求,具体需要看客户的实际场景:数据量,带宽,恢复时间,技术能力等)
正常dg同步的主备环境
这里ora11g主机是主库,ora10g主机是备库
--数据库版本
SQL> select * from v$version;
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE 11.2.0.4.0 Production
TNS for Linux: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production
---主库(ora11g)
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
READ WRITE PRIMARY ora11g YES
SQL> create table xff.t_xifenfei as select * from dba_objects;
Table created.
SQL> select count(*) from xff.t_xifenfei;
COUNT(*)
----------
86348
---备库(ora10g)
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
READ ONLY WITH APPLY PHYSICAL STANDBY ora10g YES
SQL> select count(*) from xff.t_xifenfei;
COUNT(*)
----------
86348
模拟主库(ora11g)故障,直接激活备库(ora10g)
模拟dg备库(ora10g)直接failover操作
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL; Database altered. SQL> ALTER DATABASE ACTIVATE PHYSICAL STANDBY DATABASE; Database altered.
Sat Mar 24 16:05:40 2017
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL
MRP0: Background Media Recovery cancelled with status 16037
Errors in file /u01/app/oracle/diag/rdbms/ora11g/ora11g/trace/ora11g_pr00_13428.trc:
ORA-16037: user requested cancel of managed recovery operation
Managed Standby Recovery not using Real Time Apply
Recovery interrupted!
Recovered data files to a consistent state at change 1470499
Sat Mar 24 16:05:40 2017
MRP0: Background Media Recovery process shutdown (ora11g)
Managed Standby Recovery Canceled (ora11g)
Completed: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL
Sat Mar 24 16:05:50 2017
ALTER DATABASE ACTIVATE PHYSICAL STANDBY DATABASE
ALTER DATABASE ACTIVATE [PHYSICAL] STANDBY DATABASE (ora11g)
All dispatchers and shared servers shutdown
CLOSE: killing server sessions.
CLOSE: all sessions shutdown successfully.
Sat Mar 24 16:05:50 2017
SMON: disabling cache recovery
Killing 3 processes with pids 13372,13393,13388 (all RFS) in order to
disallow current and future RFS connections. Requested by OS process 13350
Begin: Standby Redo Logfile archival
End: Standby Redo Logfile archival
RESETLOGS after incomplete recovery UNTIL CHANGE 1470499
Archived Log entry 9 added for thread 1 sequence 14 ID 0xfd5a5fc1 dest 1:
Resetting resetlogs activation ID 4250558401 (0xfd5a5fc1)
Online log /u01/app/oracle/oradata/ora11g/redo01.log: Thread 1 Group 1 was previously cleared
Online log /u01/app/oracle/oradata/ora11g/redo02.log: Thread 1 Group 2 was previously cleared
Online log /u01/app/oracle/oradata/ora11g/redo03.log: Thread 1 Group 3 was previously cleared
Standby became primary SCN: 1470497
Sat Mar 24 16:05:52 2017
Setting recovery target incarnation to 4
ACTIVATE STANDBY: Complete - Database mounted as primary
Completed: ALTER DATABASE ACTIVATE PHYSICAL STANDBY DATABASE
模拟新主库（ora10g）业务操作
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
MOUNTED PRIMARY ora10g YES
SQL> alter database open;
Database altered.
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
READ WRITE PRIMARY ora10g YES
SQL> alter system switch logfile;
System altered.
SQL> /
System altered.
SQL> /
/
System altered.
SQL>
System altered.
SQL>
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 5
Next log sequence to archive 7
Current log sequence 7
SQL> delete from xff.t_xifenfei;
86348 rows deleted.
SQL> commit;
Commit complete.
SQL> select count(*) from xff.t_xifenfei;
COUNT(*)
----------
0
原主库(ora11g)配置为新备库
---原主库(ora10g) SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 3056513024 bytes Fixed Size 2257152 bytes Variable Size 704646912 bytes Database Buffers 2332033024 bytes Redo Buffers 17575936 bytes Database mounted. SQL> Flashback database to scn 1470490; Flashback complete. SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database; OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_ ------------------------------ ------------------------------ ------------------------------ ---------- MOUNTED PRIMARY ora11g YES --现在主库(ora10g) SQL> alter database create standby controlfile as '/tmp/ctl.3'; Database altered. [oracle@ora10g ~]$ scp /tmp/ctl.3 192.168.222.11:/u01/app/oracle/oradata/ora11g/control01.ctl oracle@192.168.222.11's password: ctl.3 --现在备库(ora11g) SQL> shutdown abort ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 3056513024 bytes Fixed Size 2257152 bytes Variable Size 704646912 bytes Database Buffers 2332033024 bytes Redo Buffers 17575936 bytes Database mounted. SQL> col open_mode for a30 SQL> col database_role for a30 SQL> col HOST_NAME for a30 SQL> col flashback_on for a10 SQL> set lines 150 SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database; OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_ ------------------------------ ------------------------------ ------------------------------ ---------- MOUNTED PHYSICAL STANDBY ora11g NO SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION; Database altered.
Sat Mar 24 16:10:09 2017 ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION Attempt to start background Managed Standby Recovery process (ora11g) Sat Mar 24 16:10:09 2017 MRP0 started with pid=27, OS id=27086 MRP0: Background Managed Standby Recovery process started (ora11g) started logmerger process Sat Mar 24 16:10:14 2017 Managed Standby Recovery starting Real Time Apply Parallel Media Recovery started with 4 slaves Media Recovery start incarnation depth : 1, target inc# : 4, irscn : 1470499 Waiting for all non-current ORLs to be archived... All non-current ORLs have been archived. Clearing online redo logfile 1 /u01/app/oracle/oradata/ora11g/redo01.log Clearing online log 1 of thread 1 sequence number 7 Clearing online redo logfile 1 complete Clearing online redo logfile 2 /u01/app/oracle/oradata/ora11g/redo02.log Clearing online log 2 of thread 1 sequence number 8 Completed: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION Clearing online redo logfile 2 complete Clearing online redo logfile 3 /u01/app/oracle/oradata/ora11g/redo03.log Clearing online log 3 of thread 1 sequence number 9 Clearing online redo logfile 3 complete Media Recovery Waiting for thread 1 sequence 13 branch(resetlogs_id) 854379205 Sat Mar 24 16:10:16 2017 RFS[3]: Assigned to RFS process 27098 RFS[3]: Opened log for thread 1 sequence 13 dbid 48871109 branch 854379205 Archived Log entry 2 added for thread 1 sequence 13 rlc 854379205 ID 0xfd5a5fc1 dest 2: Sat Mar 24 16:10:16 2017 RFS[4]: Assigned to RFS process 27100 RFS[4]: Opened log for thread 1 sequence 14 dbid 48871109 branch 854379205 Archived Log entry 3 added for thread 1 sequence 14 rlc 854379205 ID 0xfd5a5fc1 dest 2: RFS[3]: Opened log for thread 1 sequence 1 dbid 48871109 branch 947798452 RFS[4]: Opened log for thread 1 sequence 3 dbid 48871109 branch 947798452 Sat Mar 24 16:10:16 2017 RFS[5]: Assigned to RFS process 27070 RFS[5]: Opened log for thread 1 sequence 2 dbid 48871109 branch 947798452 Archived Log entry 4 added for thread 1 sequence 1 rlc 947798452 ID 0x2ec1ed0 dest 2: Archived Log entry 5 added for thread 1 sequence 3 rlc 947798452 ID 0x2ec1ed0 dest 2: RFS[3]: Opened log for thread 1 sequence 4 dbid 48871109 branch 947798452 RFS[4]: Opened log for thread 1 sequence 5 dbid 48871109 branch 947798452 Archived Log entry 6 added for thread 1 sequence 5 rlc 947798452 ID 0x2ec1ed0 dest 2: Archived Log entry 7 added for thread 1 sequence 4 rlc 947798452 ID 0x2ec1ed0 dest 2: Archived Log entry 8 added for thread 1 sequence 2 rlc 947798452 ID 0x2ec1ed0 dest 2: RFS[4]: Opened log for thread 1 sequence 6 dbid 48871109 branch 947798452 Archived Log entry 9 added for thread 1 sequence 6 rlc 947798452 ID 0x2ec1ed0 dest 2: RFS[3]: Opened log for thread 1 sequence 7 dbid 48871109 branch 947798452 Archived Log entry 10 added for thread 1 sequence 7 rlc 947798452 ID 0x2ec1ed0 dest 2: Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_13_9xmyh8cs_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_14_9xmyh8dr_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_1_9xmyh8fk_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_2_9xmyh8fo_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_3_9xmyh8fm_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_4_9xmyh8g3_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_5_9xmyh8g4_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_6_9xmyh8gs_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_7_9xmyh8hl_.arc Media Recovery Log /u01/app/oracle/fast_recovery_area/ORA11GDG/archivelog/2017_03_24/o1_mf_1_8_9xmy5d3f_.arc Media Recovery Waiting for thread 1 sequence 9 (in transit) Recovery of Online Redo Log: Thread 1 Group 4 Seq 9 Reading mem 0 Mem# 0: /u01/app/oracle/oradata/ora11g/std_redo10.log
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE cancel;
Database altered.
SQL> alter database open;
Database altered.
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
Database altered.
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE cancel;
Database altered.
SQL> alter database flashback on;
Database altered.
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
READ ONLY PHYSICAL STANDBY ora11g YES
SQL> select count(*) from xff.t_xifenfei;
COUNT(*)
----------
0
--现在主库
SQL> drop table xff.t_xifenfei ;
Table dropped.
SQL> select count(*) from xff.t_xifenfei;
select count(*) from xff.t_xifenfei
*
ERROR at line 1:
ORA-00942: table or view does not exist
--现在备库
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
Database altered.
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
READ ONLY WITH APPLY PHYSICAL STANDBY ora11g YES
SQL> select count(*) from xff.t_xifenfei;
select count(*) from xff.t_xifenfei
*
ERROR at line 1:
ORA-00942: table or view does not exist
通过上述一系列操作,以前假设故障的主库,现在变成了被failover激活的主库的备库,也就是说数据库主备关系由ora11g主库—>ora10g备库变成了ora10g主库—>ora11g备库
switchover实现主备库互换
---现在主库(ora10g)
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO STANDBY WITH SESSION SHUTDOWN;
Database altered.
--现在备库(ora11g)
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;
Database altered.
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
MOUNTED PRIMARY ora11g YES
SQL> alter database open;
Database altered.
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
READ WRITE PRIMARY ora11g YES
--最新备库(ora10g)
SQL> startup
ORACLE instance started.
Total System Global Area 3056513024 bytes
Fixed Size 2257152 bytes
Variable Size 687869696 bytes
Database Buffers 2348810240 bytes
Redo Buffers 17575936 bytes
Database mounted.
Database opened.
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
Database altered.
SQL> select open_mode,database_role,(select HOST_NAME from v$instance) HOST_NAME,flashback_on from v$database;
OPEN_MODE DATABASE_ROLE HOST_NAME FLASHBACK_
------------------------------ ------------------------------ ------------------------------ ----------
READ ONLY WITH APPLY PHYSICAL STANDBY ora10g YES
--最新主库(ora11g)
SQL> alter system switch logfile;
System altered.
SQL> create table t_xifenfei as select * from dba_objects;
Table created.
SQL> select count(*) from t_xifenfei;
COUNT(*)
----------
86347
--最新备库(ora10g)
SQL> select count(*) from t_xifenfei;
COUNT(*)
----------
86347
通过switchover主备库再次互换由ora10g主库—>ora11g备库变成了ora11g主库—>ora10g备库,再次恢复到最初的状态.这个不是唯一的方法,可以通过重建dg,也能够实现类似需求.