dg搭建后oracle_redo不存在

目的：在oracle 10.2.0.4 环境中，搭建oracle dg遇到 备库redo不存在的问题，另一位同事搭建oracle 11.2.0.4 dg在备库也遇到同样的问题，如下描述处理过程。

参考

Online Redo Logs on Physical Standby (文档 ID 740675.1)

 处理流程

1.描述
生产环境dg 10.2.0.4,是由RMAN异机恢复，主库存在的redo路径在备库并未提取创建，也并未rename 日志文件，因此recover databaes完毕之后，其余MRP进程，同步应用日志，发现redo备库不存在，如下是操作日志
2.操作
尝试取消mrp
alter database recover managed standby database cancel;
确认dg角色

SQL> select dbid,name, database_role,open_mode,SWITCHOVER_STATUS,FLASHBACK_ON,PROTECTION_MODE,FORCE_LOGGING  from v$database;
       DBID NAME       DATABASE_ROLE       
----------- ---------- --------------------
       3xx9 WxxxB      PHYSICAL STANDBY    
 参数调整
SQL> alter system set standby_file_management=manual;
 查询日志组状态
SQL> select group# ,thread#,bytes/1024/1024,status from v$log;
    GROUP#    THREAD# BYTES/1024/1024 STATUS
---------- ---------- --------------- ----------------
         1          1            1024 CLEARING
         2          1            1024 CLEARING
         3          1            1024 CLEARING_CURRENT
         4          1            1024 CLEARING
         5          1            1024 CLEARING
         6          1            1024 CLEARING
         7          1            1024 CLEARING
         8          1            1024 CLEARING
8 rows selected.
手工对日志组进行clear后续进行drop 发现报错！
SQL> ALTER DATABASE CLEAR LOGFILE GROUP 1;
alter database drop logfile group 6;

ORA-01624: log 6 needed for crash recovery of instance webdb (thread 1)
ORA-00312: online log 6 thread 1: '/oracle/oradata/redolog/redo6.log'

根据MOS文档，Drop Redo Logs on Standby操作失败！！！
Sync Redo Logs on Primary and Standby 这部分区域存在一句话描述

7. Start Redo Apply:

When using Oracle Database >=10.2.0.1 and LOG_FILE_NAME_CONVERT is configured the online redo logs will

  be automatically cleared and physically created when starting recovery.

因此采用上述建议
恢复参数

SQL> alter system set standby_file_management=auto;
设置参数，与主库相同，本次并不做转换
alter system set LOG_FILE_NAME_CONVERT ='/oracle/oradata/redolog/','/oracle/oradata/redolog/' scope=spfile;
SQL> startup force mount;
重启dg生效参数
开启mrp进程
SQL>recover managed standby database disconnect from session;
观察db_alert
Managed Standby Recovery not using Real Time Apply
 parallel recovery started with 16 processes
Tue Nov 26 22:57:15 2019
Waiting for all non-current ORLs to be archived...
Tue Nov 26 22:57:15 2019
Errors in file /oracle/admin/webdb/bdump/webdb_mrp0_13806.trc:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/oracle/oradata/redolog/redo1.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Tue Nov 26 22:57:15 2019

操作系统验证-日志存在
[oracle@ytwebdb redolog]$ cd /oracle/oradata/redolog/
[oracle@ytwebdb redolog]$ ls -lrt
total 8388672
-rw-r----- 1 oracle dba 1073742336 Nov 26 22:57 redo1.log
-rw-r----- 1 oracle dba 1073742336 Nov 26 22:57 redo2.log
-rw-r----- 1 oracle dba 1073742336 Nov 26 22:57 redo3.log
-rw-r----- 1 oracle dba 1073742336 Nov 26 22:57 redo4.log