Oracle Dataguard中備庫中歸檔日志不同步

環境：RAC+單機 Dataguard
問題：啟動備庫到ADG模式時，發現后臺歸檔日志并不同步

1、在備庫中發現日志的歸檔日志不同步，內容如下：
MRP0: Background Media Recovery process shutdown (strac)
Managed Standby Recovery Canceled (strac)
Completed: alter database recover managed standby database cancel
Sun Mar 04 16:35:33 2018
Archived Log entry 96 added for thread 2 sequence 130 ID 0x971d6184 dest 1:
Sun Mar 04 16:35:33 2018
RFS[5]: Selected log 11 for thread 2 sequence 131 dbid -1759711868 branch 947273412
Sun Mar 04 16:35:34 2018
Archived Log entry 97 added for thread 2 sequence 131 ID 0x971d6184 dest 1:
RFS[5]: Selected log 11 for thread 2 sequence 132 dbid -1759711868 branch 947273412
Sun Mar 04 16:35:36 2018
Archived Log entry 98 added for thread 2 sequence 132 ID 0x971d6184 dest 1:
RFS[5]: Selected log 11 for thread 2 sequence 133 dbid -1759711868 branch 947273412
Sun Mar 04 16:39:32 2018

2、當在主庫節點1中做切換時，備庫中日志并不打印相關的日志進程信息，如果在主庫節點2中做日志切換時，備庫中是有打印日志的信息內容，內容見第一步中信息

3、通過第二步中的現象描述，可以先大概判斷為是主庫節點1中DG信息可能有問題導致歸檔日志無法同步過去

4、查詢主庫中配置歸檔位置配置的是否有錯誤信息，查詢的結果如下：
SQL> select error from v$archive_dest where target='STANDBY'
2 ;

ERROR

ORA-12154: TNS:could not resolve the connect identifier specified

SQL> select error from v$archive_dest ;

ERROR

ORA-12154: TNS:could not resolve the connect identifier specified

ERROR

ERROR

31 rows selected.
5、通過第4步中的結果，可以判斷大概一個方向 ，可能是主庫連接到備中監聽有問題導致報錯，先先TNS配置中查找原因
6、在主庫節點1中tnsping 備庫配置的服務名看是否報錯，操作如下：
[oracle@rac1:/home/oracle]$tnsping strac

TNS Ping Utility for Linux: Version 11.2.0.4.0 - Production on 04-MAR-2018 16:57:32

Copyright (c) 1997, 2013, Oracle. All rights reserved.

Used parameter files:

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.103)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = strac)))rac =
TNS-12533: TNS:illegal ADDRESS parameters
7、此時在主庫節點2中tnsping 備庫服務名發現是可以正常解析過來的
[oracle@rac2:/home/oracle]$tnsping strac

TNS Ping Utility for Linux: Version 11.2.0.4.0 - Production on 04-MAR-2018 16:58:17

Copyright (c) 1997, 2013, Oracle. All rights reserved.

Used parameter files:

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.103)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = strac)))
OK (50 msec)

8、檢查主庫節點1中的TNS文件配置，經發現主庫節點1中的TNS有很多的重復項，從而導致備庫不能同步歸檔日志

9、從主庫節點2中把TNS文件copy到主庫節點1中，此時觀察備庫中的日志可以正常打印歸檔日志同步信息，詳細內容如下：
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_1_175f9q9vwo0.arc
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_2_110f9q9qlco.arc
Media Recovery Waiting for thread 1 sequence 176
Fetching gap sequence in thread 1, gap sequence 176-176
Sun Mar 04 16:00:09 2018
RFS[6]: Opened log for thread 1 sequence 176 dbid -1759711868 branch 947273412
Archived Log entry 78 added for thread 1 sequence 176 rlc 947273412 ID 0x971d6184 dest 2:
Sun Mar 04 16:00:21 2018
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_1_176f9q9w9h6.arc
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_2_111f9q9qmng.arc
Media Recovery Waiting for thread 1 sequence 177
Fetching gap sequence in thread 1, gap sequence 177-177
Sun Mar 04 16:00:41 2018
RFS[6]: Opened log for thread 1 sequence 177 dbid -1759711868 branch 947273412
Archived Log entry 79 added for thread 1 sequence 177 rlc 947273412 ID 0x971d6184 dest 2:
Sun Mar 04 16:00:51 2018
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_1_177f9q9x92z.arc
Media Recovery Waiting for thread 1 sequence 178
Fetching gap sequence in thread 1, gap sequence 178-178
Sun Mar 04 16:00:51 2018
RFS[6]: Opened log for thread 1 sequence 178 dbid -1759711868 branch 947273412
Archived Log entry 80 added for thread 1 sequence 178 rlc 947273412 ID 0x971d6184 dest 2:
Sun Mar 04 16:01:01 2018
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_1_178f9q9xmc8.arc
Media Recovery Waiting for thread 1 sequence 179
Fetching gap sequence in thread 1, gap sequence 179-179
Sun Mar 04 16:01:01 2018
RFS[6]: Opened log for thread 1 sequence 179 dbid -1759711868 branch 947273412
Archived Log entry 81 added for thread 1 sequence 179 rlc 947273412 ID 0x971d6184 dest 2:
Sun Mar 04 16:01:11 2018
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_1_179f9q9xxgx.arc
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_2_112f9q9qmwy.arc
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_2_113f9q9qmyd.arc
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_2_114f9q9qncn.arc
Media Recovery Waiting for thread 1 sequence 180
Fetching gap sequence in thread 1, gap sequence 180-180
Sun Mar 04 16:01:11 2018
RFS[6]: Opened log for thread 1 sequence 180 dbid -1759711868 branch 947273412
Archived Log entry 82 added for thread 1 sequence 180 rlc 947273412 ID 0x971d6184 dest 2:
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_1_180f9q9y7sn.arc
Media Recovery Log /archlog/STRAC/archivelog/2018_03_04/o1_mf_2_115f9q9qncr.arc
Media Recovery Waiting for thread 1 sequence 181

總結說明：
1、當發現備庫中有日志不同步時，可以先從判斷配置DG配置項著手，然后通過v$archive_dest 表可以查看當前的歸檔狀態是否正常，本環境中由于原來的DG環境是正常的，后面出現的問題，可以判斷初步搭建環境是Ok的。
2、通過v$archive_dest 查詢當前的DG的歸檔日志信息，如果里面有報錯信息，可以提供一個大概的參考范圍，方便我們定位問題