Oracle 11G DataGuard ORA-16086问题修复详细过程

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1，问题描述，standby从库没有应用redo日志
Tue Jul 22 09:05:07 2014
RFS[8852]: Assigned to RFS process 12956
RFS[8852]: Identified database type as 'physical standby': Client is ARCH pid 16028
Tue Jul 22 09:05:09 2014
RFS[8853]: Assigned to RFS process 12958
RFS[8853]: Identified database type as 'physical standby': Client is LGWR SYNC pid 15950
Primary database is in MAXIMUM AVAILABILITY mode
Standby controlfile consistent with primary
Standby controlfile consistent with primary
RFS[8853]: No standby redo logfiles selected (reason:7)
Errors in file /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/powerdes_rfs_12958.trc:
ORA-16086: Redo data cannot be written to the standby redo log
Tue Jul 22 09:11:07 2014
RFS[8854]: Assigned to RFS process 12976
RFS[8854]: Identified database type as 'physical standby': Client is ARCH pid 16028
Tue Jul 22 09:11:07 2014
RFS[8855]: Assigned to RFS process 12978
RFS[8855]: Identified database type as 'physical standby': Client is LGWR SYNC pid 15950
Primary database is in MAXIMUM AVAILABILITY mode
Standby controlfile consistent with primary
Standby controlfile consistent with primary
RFS[8855]: No standby redo logfiles selected (reason:7)
Errors in file /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/powerdes_rfs_12978.trc:
ORA-16086: Redo data cannot be written to the standby redo log

2，在从库查看redo日志信息
SQL> show parameter log_file_name_convert;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
log_file_name_convert string /home/oradata/powerdes, /home/
oradata/powerdes
SQL>
SQL>
SQL> select group#,member from v$logfile;

GROUP#
----------
MEMBER
--------------------------------------------------------------------------------
3
/home/oradata/powerdes/redo03.log

2
/home/oradata/powerdes/redo02.log

1
/home/oradata/powerdes/redo01.log

SQL> select GROUP#,FIRST_CHANGE#,SEQUENCE#,STATUS from v$log;

GROUP# FIRST_CHANGE# SEQUENCE# STATUS
---------- ------------- ---------- ----------------
1 1.0533E+10 23999 CLEARING_CURRENT
2 1.0533E+10 23997 CLEARING
3 1.0533E+10 23998 CLEARING

SQL>

SQL> select group#,bytes/1024/1024,members,status from v$log;

GROUP# BYTES/1024/1024 MEMBERS STATUS
---------- --------------- ---------- ----------------
1 50 1 CLEARING
2 50 1 CLEARING_CURRENT
3 50 1 CLEARING

SQL>

先暂停redo log日志：
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

执行更新日志操作：
alter database clear logfile group 1;
alter database clear logfile group 2;
alter database clear logfile group 3;

SQL> alter database clear logfile group 1;
alter database clear logfile group 1
*
ERROR at line 1:
ORA-01156: recovery or flashback in progress may need access to files

报错是因为MFS进程锁定日志了，所以需要先停应用再更新日志操作
alter database recover managed standby database cancel;
SQL> alter database recover managed standby database cancel;
Database altered.
SQL> alter database clear logfile group 1;
Database altered.
SQL> alter database clear logfile group 2;
Database altered.
SQL> alter database clear logfile group 3;
Database altered.
SQL>

然后再执行redo应用
SQL> alter database recover managed standby database disconnect from session;
Database altered.
SQL>

查看redo应用情况
SQL> select name,creator,sequence#,applied,completion_time from v$archived_log;
都是NO

3，重建redo log
再查看下看一下现在的redo log状态
select group#,bytes/1024/1024,members,status from v$log;
SQL> select group#,bytes/1024/1024,members,status from v$log;

GROUP# BYTES/1024/1024 MEMBERS STATUS
---------- --------------- ---------- ----------------
1 50 1 UNUSED
2 50 1 CLEARING
3 50 1 CLEARING_CURRENT

redo log损坏，但是clear不管用，因为是备库 read-only不让切换日志
重建redo日志文件，先停redo应用
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

alter database add logfile group 4 ('/home/oradata/powerdes/redo04.log') size 50M;
alter database add logfile group 5 ('/home/oradata/powerdes/redo05.log') size 50M;
alter database add logfile group 6 ('/home/oradata/powerdes/redo06.log') size 50M;

日志管理是自动的，所以不能操作，要先设置成手动管理的
SQL> alter system set standby_file_management='manual';
System altered.
SQL> alter database add logfile group 4 ('/home/oradata/powerdes/redo04.log') size 50M;
Database altered.
SQL> alter database add logfile group 5 ('/home/oradata/powerdes/redo05.log') size 50M;
Database altered.
SQL> alter database add logfile group 6 ('/home/oradata/powerdes/redo06.log') size 50M;
Database altered.
SQL>

查看一下日志状态
SQL> select group#,bytes/1024/1024,members,status from v$log;
GROUP# BYTES/1024/1024 MEMBERS STATUS
---------- --------------- ---------- ----------------
1 50 1 CLEARING_CURRENT
2 50 1 CLEARING
3 50 1 CLEARING
4 50 1 UNUSED
5 50 1 UNUSED
6 50 1 UNUSED

6 rows selected.

清空redo日志组
SQL>
alter database clear logfile group 1;
alter database clear logfile group 2;
alter database clear logfile group 3;

SQL>
alter database clear logfile group 1;
alter database clear logfile group 2;
alter database clear logfile group 3;

Database altered.

SQL>
Database altered.

SQL>
Database altered.

SQL>

查看redo 日志组信息
SQL> select group#,bytes/1024/1024,members,status from v$log;
GROUP# BYTES/1024/1024 MEMBERS STATUS
---------- --------------- ---------- ----------------
1 50 1 CURRENT
2 50 1 UNUSED
3 50 1 UNUSED
4 50 1 UNUSED
5 50 1 UNUSED
6 50 1 UNUSED

6 rows selected.

alter database drop logfile group 1;
alter database drop logfile group 2;
alter database drop logfile group 3;

SQL>
alter database drop logfile group 1;
alter database drop logfile group 2;
alter database drop logfile group 3;

Database altered.

SQL>
Database altered.

SQL> alter database drop logfile group 3
*
ERROR at line 1:
ORA-01623: log 3 is current log for instance powerdes (thread 1) - cannot drop
ORA-00312: online log 3 thread 1: '/home/oradata/powerdes/redo03.log'

SQL>

4，检查归档文件是否完整
从库redo log损坏了的话，只要从库的归档日志在，还是可以修复的，不用重新做Standy。
从库上执行check：
SQL> SELECT DISTINCT THREAD#,max(SEQUENCE#) OVER(PARTITION BY THREAD#) A FROM V$ARCHIVED_LOG;
THREAD# A
---------- ----------
123826
SQL>

主库上执行check：
SQL> SELECT DISTINCT THREAD#,max(SEQUENCE#) OVER(PARTITION BY THREAD#) A FROM V$ARCHIVED_LOG;
THREAD# A
---------- ----------
124022

SQL>
取出primary和standy库上各线程已经归档文件最大序列号，看到两者不相同，必须将多出的序列号对应的归档文件复制到standy库。
也就是说主库从库的归档日志相差蛮大的。

如何查看归档路径，最高可用模式的时候 dg会尽力的让日志应用到standby
去查一下
SELECT GROUP#,THREAD#,SEQUENCE#,ARCHIVED,STATUS FROM V$STANDBY_LOG;
从库：
SQL> SELECT GROUP#,THREAD#,SEQUENCE#,ARCHIVED,STATUS FROM V$STANDBY_LOG;
no rows selected
SQL>

主库：
SQL> SELECT GROUP#,THREAD#,SEQUENCE#,ARCHIVED,STATUS FROM V$STANDBY_LOG;
no rows selected
SQL>
表名从库的standby log都空的，需要重建standby log。

5，确定归档日志有没有写到从库：
所以用的lgwr进程，用lgwr进程进行传输日志，而其他模式用arch传输日志是等到日志写到归档的过程中传输过去，最近你没有改过从库的保护模式吧。
主库上查看下redo log的大小：
select GROUP#,BYTES/1024/1024,STATUS from v$log;
SQL> select GROUP#,BYTES/1024/1024,STATUS from v$log;
GROUP# BYTES/1024/1024 STATUS
---------- --------------- ----------------
1 50 CURRENT
2 50 INACTIVE
3 50 ACTIVE

SQL>

确定日志有没有写到从库：
执行： select name,sequence#,applied from v$archived_log;
NAME
--------------------------------------------------------------------------------
SEQUENCE# APPLIED
---------- ---------
/oracle/app/oracle/flash_recovery_area/archivelog/1_24161_821708334.dbf
24161 NO

/oracle/app/oracle/flash_recovery_area/archivelog/1_24162_821708334.dbf
24162 NO

从库上归档日志：
NAME
--------------------------------------------------------------------------------
SEQUENCE# APPLIED
---------- ---------
/data/oracle/oradgdata/standby_archive/1_24072_821708334.dbf
24072 NO

2800 rows selected.
看到这里，从库上，最后一个日志是24072，比主库上的24162要低很多，

再去查下主库的归档日志路径：
select name from v$archived_log;找到归档日志路径/oracle/app/oracle/flash_recovery_area/archivelog/
ll /oracle/app/oracle/flash_recovery_area/archivelog/看到最后一个归档日志是：
-rw-r----- 1 oracle oinstall 2808832 Jul 22 09:24 1_24162_821708334.dbf
-rw-r----- 1 oracle oinstall 3072512 Jul 22 09:30 1_24163_821708334.dbf
再去主库的归档日志路径上面check下，是否有从库最后一个归档日志24072
[oracle@localhost ~]$ ll /oracle/app/oracle/flash_recovery_area/archivelog/*24072*.dbf
-rw-r----- 1 oracle oinstall 1992704 Jul 22 01:00 /oracle/app/oracle/flash_recovery_area/archivelog/1_24072_821708334.dbf
[oracle@localhost ~]$

检查下主库从库的归档管理模式
从库：
SQL> show parameter standby_file_management;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
standby_file_management string MANUAL
SQL>

主库：
SQL> show parameter standby_file_management;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
standby_file_management string AUTO
SQL>

看到从库跟主库不一致，需要手动将从库上面的MANUAL修改成AUTO。
alter system set standby_file_management='AUTO';
SQL> alter system set standby_file_management='AUTO';
System altered.
SQL>
SQL> show parameter standby_file_management;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
standby_file_management string AUTO
SQL>

去主库上查看一下归档日志的状态
SQL> show parameter log_archive_dest_state_2;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_state_2 string ENABLE
log_archive_dest_state_20 string enable
log_archive_dest_state_21 string enable
log_archive_dest_state_22 string enable
log_archive_dest_state_23 string enable
log_archive_dest_state_24 string enable
log_archive_dest_state_25 string enable
log_archive_dest_state_26 string enable
log_archive_dest_state_27 string enable
log_archive_dest_state_28 string enable
log_archive_dest_state_29 string enable
SQL>

6，检查alert信息
因为主库1点有oracle归档日志，所以去主库从库看下alert日志信息：
主库信息：
ll /oracle/app/oracle/diag/rdbms/pdunq/powerdes/trace/alert_powerdes.log
Tue Jul 22 01:00:02 2014
ALTER SYSTEM ARCHIVE LOG
Tue Jul 22 01:00:02 2014
Thread 1 advanced to log sequence 24073 (LGWR switch)
Current log# 1 seq# 24073 mem# 0: /home/oradata/powerdes/redo01.log
Archived Log entry 46639 added for thread 1 sequence 24072 ID 0xca2ab4eb dest 1:
Tue Jul 22 01:00:17 2014
Errors in file /oracle/app/oracle/diag/rdbms/pdunq/powerdes/trace/powerdes_lgwr_15950.trc:
ORA-16086: Redo data cannot be written to the standby redo log
LGWR: Failed to archive log 2 thread 1 sequence 24074 (16086)
Thread 1 advanced to log sequence 24074 (LGWR switch)
Current log# 2 seq# 24074 mem# 0: /home/oradata/powerdes/redo02.log
Tue Jul 22 01:00:19 2014
Archived Log entry 46641 added for thread 1 sequence 24073 ID 0xca2ab4eb dest 1:
Tue Jul 22 01:02:28 2014
backup piece header validation failure for handle /data/oracle/backup/data/ctl_auto/c-3391761643-20140721-00
backup piece header validation failure for handle /data/oracle/backup/data/ctl_auto/c-3391761643-20140721-01

ll /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/alert_powerdes.log
从库信息：
Tue Jul 22 01:04:48 2014
RFS[8692]: Assigned to RFS process 10970
RFS[8692]: Identified database type as 'physical standby': Client is ARCH pid 16028
Tue Jul 22 01:04:49 2014
RFS[8693]: Assigned to RFS process 10972
RFS[8693]: Identified database type as 'physical standby': Client is LGWR SYNC pid 15950
Primary database is in MAXIMUM AVAILABILITY mode
Standby controlfile consistent with primary
Standby controlfile consistent with primary
RFS[8693]: No standby redo logfiles selected (reason:7)
Errors in file /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/powerdes_rfs_10972.trc:
ORA-16086: Redo data cannot be written to the standby redo log
Tue Jul 22 01:10:48 2014
RFS[8694]: Assigned to RFS process 10989
RFS[8694]: Identified database type as 'physical standby': Client is ARCH pid 16028
Tue Jul 22 01:10:51 2014
RFS[8695]: Assigned to RFS process 10992
RFS[8695]: Identified database type as 'physical standby': Client is LGWR SYNC pid 15950

7，在从库上操作，还原昨天的logfile组：
先停止redo应用
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
然后设置成manual模式
alter system set standby_file_management='MANUAL';
重建redo日志文件
alter database add logfile group 1 ('/home/oradata/powerdes/redo01.log') size 50M;
alter database add logfile group 2 ('/home/oradata/powerdes/redo02.log') size 50M;
alter database drop logfile group 4;
alter database drop logfile group 5;
alter database drop logfile group 6;
SQL> alter database add logfile group 1 ('/home/oradata/powerdes/redo01.log') size 50M;
alter database add logfile group 1 ('/home/oradata/powerdes/redo01.log') size 50M
*
ERROR at line 1:
ORA-01275: Operation ADD LOGFILE is not allowed if standby file management is
automatic.
SQL>
看到报错，需要去从库删除已经存在的redo01和redo02日志
[oracle@localhost dbs]$ mv /home/oradata/powerdes/redo01.log /home/oradata/powerdes/bak.redo01.log.20140722
[oracle@localhost dbs]$ mv /home/oradata/powerdes/redo02.log /home/oradata/powerdes/bak.redo02.log.20140722
然后再在从库执行如下还原日志操作，成功了
alter database add logfile group 1 ('/home/oradata/powerdes/redo01.log') size 50M;
alter database add logfile group 2 ('/home/oradata/powerdes/redo02.log') size 50M;
alter database drop logfile group 4;
alter database drop logfile group 5;
alter database drop logfile group 6;

去主库从库执行，不分先后顺序：
alter database add standby logfile group 4 ('/home/oradata/powerdes/redo_dg_01.log') size 50m;
alter database add standby logfile group 5 ('/home/oradata/powerdes/redo_dg_02.log') size 50m;
alter database add standby logfile group 6 ('/home/oradata/powerdes/redo_dg_03.log') size 50m;

执行redo应用：
alter database recover managed standby database disconnect from session;
SQL> alter database recover managed standby database disconnect from session;
Database altered.
SQL>

select name,sequence#,applied from v$archived_log;
还是No，没有被应用成YES。
alter system set standby_file_management='AUTO';
SQL> alter system set standby_file_management='AUTO';
System altered.
SQL>
SQL> show parameter standby_file_management;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
standby_file_management string AUTO
SQL>

然后再在从库上面执行redo应用
alter database recover managed standby database disconnect from session;

8，尝试下关闭再重启从库
SHUTDOWN IMMEDIATE;
下面是alert信息：

Tue Jul 22 11:04:42 2014
MRP0: Background Media Recovery cancelled with status 16037
Errors in file /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/powerdes_pr00_13338.trc:
ORA-16037: user requested cancel of managed recovery operation
Recovery 
Errors in file /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/powerdes_pr00_13338.trc:
ORA-16037: user requested cancel of managed recovery operation
Waiting for MRP0 pid 13335 to terminate
Tue Jul 22 11:04:44 2014
MRP0: Background Media Recovery process shutdown (powerdes)
License high water mark = 40
ALTER DATABASE CLOSE NORMAL
Tue Jul 22 11:04:45 2014
SMON: disabling cache recovery
Completed: ALTER DATABASE CLOSE NORMAL
ALTER DATABASE DISMOUNT
Completed: ALTER DATABASE DISMOUNT
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
Tue Jul 22 11:04:46 2014
ARCH shutting down
Tue Jul 22 11:04:46 2014
ARCH shutting down
Tue Jul 22 11:04:46 2014
ARCj: Archival stoppedTue Jul 22 11:04:46 2014
ARCH shutting downTue Jul 22 11:04:46 2014


ARCH shutting down


ARCH shutting down
Tue Jul 22 11:04:46 2014
ARCH shutting downARCi: Archival stopped


Tue Jul 22 11:04:46 2014
ARCH shutting down
Tue Jul 22 11:04:46 2014
ARCH shutting down
ARCf: Archival stopped
ARCg: Archival stoppedARCh: Archival stopped
Tue Jul 22 11:04:46 2014


ARCH shutting downARCe: Archival stopped
Tue Jul 22 11:04:46 2014


ARCH shutting downTue Jul 22 11:04:46 2014
ARCd: Archival stopped
ARCH shutting downTue Jul 22 11:04:46 2014




ARCc: Archival stoppedTue Jul 22 11:04:46 2014
ARCH shutting downARCH shutting down
Tue Jul 22 11:04:46 2014


Tue Jul 22 11:04:46 2014


Tue Jul 22 11:04:46 2014
ARCH shutting downTue Jul 22 11:04:46 2014
ARCH shutting down
ARCH shutting downARCa: Archival stopped


ARC9: Archival stopped
ARCH shutting down
ARC7: Archival stopped


ARCb: Archival stopped
ARC6: Archival stoppedARC5: Archival stoppedTue Jul 22 11:04:46 2014




ARCH shutting downARC8: Archival stopped


ARC4: Archival stopped
ARC2: Archival stopped
ARC3: Archival stopped
Tue Jul 22 11:04:46 2014
ARCH shutting down
ARC1: Archival stoppedTue Jul 22 11:04:46 2014


ARCH shutting down
ARC0: Archival stopped
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
Archive process shutdown avoided: 0 active
Tue Jul 22 11:04:48 2014
Stopping background process VKTM: 
Tue Jul 22 11:04:50 2014
Instance shutdown complete

再启动从库
STARTUP MOUNT;
再应用redo应用
alter database recover managed standby database disconnect from session;
查看是否有yes
select name,sequence#,applied from v$archived_log;
select sequence#,applied from v$archived_log;
还是NO，没有被应用
最后执行
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
在检查select sequence#,applied from v$archived_log;还是No，日志没有被应用。

查看归档日志路径：
select name from v$archived_log;

查看主库备份记录策略：
RMAN> show retention policy;
RMAN configuration parameters for database with db_unique_name PDUNQ are:
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 15 DAYS;

9，从库上面执行恢复归档日志，这个过程比较慢，耗时比较长
recover automatic standby database ;
SQL> recover automatic standby database ;

ORA-00279: change 10533608939 generated at 07/22/2014 14:00:38 needed for
thread 1
ORA-00289: suggestion :
/data/oracle/oradgdata/standby_archive/1_24178_821708334.dbf
ORA-00280: change 10533608939 for thread 1 is in sequence #24178
ORA-00278: log file
'/data/oracle/oradgdata/standby_archive/1_24178_821708334.dbf' no longer needed
for this recovery
ORA-16145: archival for thread# 1 sequence# 24178 in progress

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
ORA-16145: archival for thread# 1 sequence# 24178 in progress

SQL>

如下是alert日志信息：
Media Recovery Log /data/oracle/oradgdata/standby_archive/1_24177_821708334.dbf
Tue Jul 22 14:16:58 2014
Media Recovery Log /data/oracle/oradgdata/standby_archive/1_24178_821708334.dbf
Tue Jul 22 14:16:59 2014
MRP: Archival for thread 1 sequence 24178 in progress
Standby Managed Recovery operation not detected
Errors with log /data/oracle/oradgdata/standby_archive/1_24178_821708334.dbf
Errors in file /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/powerdes_pr00_13910.trc:
ORA-16145: archival for thread# 1 sequence# 24178 in progress
Tue Jul 22 14:17:13 2014
ORA-279 signalled during: ALTER DATABASE RECOVER automatic standby database ...
ALTER DATABASE RECOVER CONTINUE DEFAULT
Media Recovery Log /data/oracle/oradgdata/standby_archive/1_24178_821708334.dbf
Tue Jul 22 14:17:13 2014
MRP: Archival for thread 1 sequence 24178 in progress
Standby Managed Recovery operation not detected
Errors with log /data/oracle/oradgdata/standby_archive/1_24178_821708334.dbf
Errors in file /oracle/app/oracle/diag/rdbms/pddgunq/powerdes/trace/powerdes_pr00_13910.trc:
ORA-16145: archival for thread# 1 sequence# 24178 in progress
ORA-16145 signalled during: ALTER DATABASE RECOVER CONTINUE DEFAULT ...
ALTER DATABASE RECOVER CANCEL
Media Recovery Canceled
Completed: ALTER DATABASE RECOVER CANCEL

然后启动redo应用
alter database recover managed standby database disconnect from session;
SQL> alter database recover managed standby database disconnect from session;
Database altered.

去从库上检查日志是否已经应用成YES
SQL> select sequence#,applied from v$archived_log;
SEQUENCE# APPLIED
---------- ---------
24172 YES
24170 YES
24169 YES
24173 YES
24176 YES
24177 YES
2800 rows selected.

再去主库上切换下日志，看下新的24178归档日志是否传输过来，是否应用成YES：
alter system switch logfile;
SQL> alter system switch logfile;
System altered.
SQL>

去从库上面执行检查
SQL> select sequence#,applied from v$archived_log;
SEQUENCE# APPLIED
---------- ---------
24170 YES
24169 YES
24173 YES
24176 YES
24177 YES
24178 IN-MEMORY

2800 rows selected.
再继续检查check下，applied就变成YES了
SEQUENCE# APPLIED
---------- ---------
24170 YES
24169 YES
24173 YES
24176 YES
24177 YES
24178 YES
2800 rows selected.

停止redo应用
alter database recover managed standby database cancel;
再打开open模式，将从库打开供大家查询数据
alter database open read only;
再起动redo应用
alter database recover managed standby database disconnect from session;

10，总结2个操作：
一是重建了redo log，添加了3组standby log：
alter database add logfile group 1 ('/home/oradata/powerdes/redo01.log') size 50M;
alter database add logfile group 2 ('/home/oradata/powerdes/redo02.log') size 50M;
alter database drop logfile group 4;
alter database drop logfile group 5;
alter database drop logfile group 6;
alter database add standby logfile group 4 ('/home/oradata/powerdes/redo_dg_01.log') size 50m;
alter database add standby logfile group 5 ('/home/oradata/powerdes/redo_dg_02.log') size 50m;
alter database add standby logfile group 6 ('/home/oradata/powerdes/redo_dg_03.log') size 50m;

二是在从库上恢复归档日志：
RECOVER AUTOMATIC STANDBY DATABASE ;

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