11.2 rman 备份 放在DG 库上跑，可能遇到的问题。
问题：
在这里 DB DG 切换，发现一个问题，主库A的模式切换到备库模式 时候，该主库日志会有如下提示：
ORA-17627: ORA-01017: invalid username/password; logon denied
ORA-17629: Cannot connect to the remote database server
检查：
1． 经过检查，发现该报错来自于rman@pdbdb03 (TNS V1-V3） 进程
*** MODULE NAME:(rman@pdbdb03 (TNS V1-V3)) 2020-06-08 01:31:36.843
krsd_get_primary_connect_string
询问了，备份是跑数据库 A 上，备份也是正常的， 说明这个报错不会影响备份。
附录：通过检查，虽然有这个这个报错，但是归档日志，仍然仍然可以备份成功的，带过来的问题，可能是如果是备份在standby, 那么归档日志没办法自动清理。需要
调整备份策略从 tape 调整为 applyed to standby.
2． 经过分析，应该是触发了一个bug Bug 17580082 - ACTIVE STANDBY - RMAN-06820: WARNING: FAILED TO ARCHIVE CURRENT LOG AT PRIMARY
Status: 32 - Not a Bug. To Filer
在11.2 环境下，如果rman 备份发生在备库，oracle 会强制主库做一个switch logfile 操作。如果连不上主库，就会触发这个报错。
as of 11.2.0.4, we now include the current standby redo log as part of an RMAN archivelog backup at the standby site. This is achieved by forcing a log switch at the primary site.
规避方法：
1。如果备份 发起在 容灾库备份，备份脚本 使用用户名+ 密码方式登录。
Instead put in the username and password for the SYSDBA user:
$ rman target sys/password@stby
而不是That is, do not use just the "/" (operating system authentication) connect to the standby database: 这样会导致 备库的备份连接不到主库，产生这个报错的
$ rman target /
2。这个Bug Bug 21476308/17580082 在如下版本得到修复，12.1.0.2.170117 (Jan 2017) Database Patch Set Update (DB PSU)
ORA-1017 by RMAN When Connecting to Target with Username/Password from RMAN Operations Platforms affected Generic (all / most platforms affected)
Fixed:
12.2.0.1 (Base Release)
12.1.0.2.170117 (Jan 2017) Database Patch Set Update (DB PSU)
（Enhancement Request/Bug 18070699 allows for the use of other
user/password apart from sys password to connect to remote database for RMAN
operation.
Bug 18070699: ALLOW NON-SYS USERNAME GRANTED SYSDBA TO
RESYNC DB_UNIQUE_NAME ALL
Patches are available for this issue by searching bug 21476308 for patch name or number. ）
附录：通过检查，虽然有这个这个报错，但是归档日志，仍然仍然可以备份成功。
For UNIX/Linux Platforms
$ export NLS_DATE_FORMAT='yyyy/mm/dd hh24:mi:ss'
$ rman target /
...
list archivelog all backed up 1 times to sbt_tape;
315876 1 298408 A 2020/10/19 06:28:58
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298408_hrsk2qmc_.arc
315877 1 298409 A 2020/10/19 06:40:19
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298409_hrsk332y_.arc
315879 1 298410 A 2020/10/19 06:40:26
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298410_hrsk49h9_.arc
315878 1 298411 A 2020/10/19 06:40:34
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298411_hrsk3lqv_.arc
315881 1 298412 A 2020/10/19 06:40:39
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298412_hrsk52qw_.arc
315882 1 298413 A 2020/10/19 06:40:44
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298413_hrsk55cy_.arc
315880 1 298414 A 2020/10/19 06:40:49
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298414_hrsk4c19_.arc
315886 1 298415 A 2020/10/19 06:40:54
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298415_hrsk6h0d_.arc
315884 1 298416 A 2020/10/19 06:41:00
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298416_hrsk60wr_.arc
315887 1 298417 A 2020/10/19 06:41:06
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298417_hrsk6y9r_.arc
315883 1 298418 A 2020/10/19 06:41:11
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298418_hrsk53po_.arc
315888 1 298419 A 2020/10/19 06:41:17
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298419_hrsk7dnl_.arc
315890 1 298420 A 2020/10/19 06:41:24
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298420_hrsk8812_.arc
315885 1 298421 A 2020/10/19 06:41:32
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298421_hrsk6csj_.arc
315891 1 298422 A 2020/10/19 06:41:41
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298422_hrsk8joc_.arc
315893 1 298423 A 2020/10/19 06:41:52
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298423_hrsk92no_.arc
315895 1 298424 A 2020/10/19 06:42:05
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298424_hrsk9rsq_.arc
315889 1 298425 A 2020/10/19 06:42:17
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298425_hrsk7n18_.arc
315894 1 298426 A 2020/10/19 06:42:28
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298426_hrsk9mdt_.arc
315897 1 298427 A 2020/10/19 06:42:35
Name: /db/db/fra/db/archivelog/2020_10_19/o1_mf_1_298427_hrskbhkw_.arc
