Oracle 11gR2 Database和Active Data Guard迁移案例


客户一套核心系统由一台Oracle Database 11.2.0.3.4单机和一台Active Data Guard组成,分别运行在两台PC服务器上,Oracle Linux 5.8 x86_64bit操作系统,两台服务器都未接存储设备;由于原有设备老旧等原因,现在要将这套Oracle数据库系统(主库和ADG库)迁移到新采购的两台服务器上,不跨版本,也不跨平台。为了最小化停机时间,我们先用目前最新的RMAN 0级备份在两台新服务器上restore database,之后将到目前为止的所有1级备份和归档日志restore和recover到两个数据库上,在主数据库正常停机之后把剩余的归档和在线Redo日志文件应用到两个新数据库,使他们的数据到最新,且是一致的,最后打开主数据库,恢复ADG的同步,整个过程从凌晨0点开始停机,一直持续到了4:20才迁移成功,之间遇到了不少小的问题,再次进行记录:

1.RMAN报错。

RMAN在应用部分归档日志之后收到如下报错:
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 11/13/2014 00:03:03
ORA-00283: recovery session canceled due to errors
RMAN-11003: failure during parse/execution of SQL statement: alter database recover logfile '/oradata/bak/archivelog/2014_11_12/o1_mf_1_62193_b65oryl5_.arc'
ORA-00283: recovery session canceled due to errors
ORA-19755: could not open change tracking file
ORA-19750: change tracking file: '/u01/app/oracle/block_change_file'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3

执行下面的SQL禁用block change tracking,数据库即可继续正常的应用archivelog:

SQL > alter database disable block change tracking;

Database altered.

2.resetlogs之后检查主库和备库的日志同步情况。

 通常在主库执行以下的SQL语句可以用于检查主库和备库日志同步情况:
SQL> select dest_id,thread#,max(sequence#) from v$archived_log where resetlogs_change#=936497858  group by dest_id,thread#;

  DEST_ID    THREAD# MAX(SEQUENCE#)
---------- ---------- --------------
        2          1              9
        1          1              9

    由于主数据库在打开的时候执行了alter database open resetlogs,所以查询v$archived_log要跟上resetlogs_change#,确保查看的是现在数据库的归档情况,resetlogs_change#可以通过v$database.resetlogs_change#获得,另外,由于resetlogs打开了数据库,所以sequence#重新开始计数。


3.对活动的Standby LogFile的处理。

  停止主数据库之后,我们是想将原来的所有Online Redo Logfile和Standby Logfile都拷贝到新服务器,通过alter databae rename file ... to ...的方式进行重命名,没想到的是Active的Standby Logfile无法进行重命名(收到报错:ORA-01511: error in renaming log/data files),但又必须将Standby Logfile文件放在指定的目录下,下面是查询v$logfile的状态:

SQL> select group#,member from v$logfile;

    GROUP#
----------
MEMBER
--------------------------------------------------------------------------------
        3
/oradata/orcl/REDO03.LOG

        2
/oradata/orcl/REDO02.LOG

        1
/oradata/orcl/REDO01.LOG


    GROUP#
----------
MEMBER
--------------------------------------------------------------------------------
        4
/u01/app/oracle/oradata/orcl/sredo01.log

        5
/oradata/orcl/sredo02.log

        6
/oradata/orcl/sredo03.log


    GROUP#
----------
MEMBER
--------------------------------------------------------------------------------
        7
/oradata/orcl/sredo04.log


7 rows selected.

group# 4是主数据库之前的Active Standby Logfile,无法对其进行alter database rename file操作。

SQL> alter database drop logfile group 4;
alter database drop logfile group 4
*
ERROR at line 1:
ORA-00315: log 4 of thread 1, wrong thread # 0 in header
ORA-00312: online log 4 thread 1: '/u01/app/oracle/oradata/orcl/sredo01.log'

尝试DROP GROUP组失败。

SQL> alter database add logfile member '/oradata/orcl/sredo01.log' to group 4;
alter database add logfile member '/oradata/orcl/sredo01.log' to group 4
*
ERROR at line 1:
ORA-16161: Cannot mix standby and online redo log file members for group 4

尝试添加成员失败。

SQL> ALTER DATABASE CLEAR LOGFILE GROUP 4;   
ALTER DATABASE CLEAR LOGFILE GROUP 4
*
ERROR at line 1:
ORA-00350: log 4 of instance orcl (thread 1) needs to be archived
ORA-00312: online log 4 thread 1: '/u01/app/oracle/oradata/orcl/sredo01.log'

由于未归档所以直接CLEAR失败。

SQL> ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 4;

Database altered.

CLEAR UNARCHIVED成功。
 对Standby Logfile的处理办法和对Online Redo Logfile的处理办法一致。

SQL> select group#,thread#,status from v$standby_log;

    GROUP#    THREAD# STATUS
---------- ---------- ----------
        4          1 UNASSIGNED
        5          1 UNASSIGNED
        6          1 UNASSIGNED
        7          1 UNASSIGNED

SQL> select member from v$logfile;

MEMBER
--------------------------------------------------------------------------------
/oradata/orcl/REDO03.LOG
/oradata/orcl/REDO02.LOG
/oradata/orcl/REDO01.LOG
/u01/app/oracle/oradata/orcl/sredo01.log
/oradata/orcl/sredo02.log
/oradata/orcl/sredo03.log
/oradata/orcl/sredo04.log

7 rows selected.

SQL> alter database drop logfile group 4;

Database altered.

成功DROP该日志组。

SQL> select member from v$logfile;

MEMBER
--------------------------------------------------------------------------------
/oradata/orcl/REDO03.LOG
/oradata/orcl/REDO02.LOG
/oradata/orcl/REDO01.LOG
/oradata/orcl/sredo02.log
/oradata/orcl/sredo03.log
/oradata/orcl/sredo04.log

6 rows selected.
       
SQL> select group#,thread#,bytes/1024/1024 mb from v$standby_log;

    GROUP#    THREAD#        MB
---------- ---------- ----------
        5          1        50
        6          1        50
        7          1        50


SQL> ALTER DATABASE ADD STANDBY LOGFILE  group 4 ('/oradata/orcl/sredo01.log') SIZE 50M;

Database altered.

添加GROUP 4新的位置。

SQL> select member from v$logfile;

MEMBER
--------------------------------------------------------------------------------
/oradata/orcl/REDO03.LOG
/oradata/orcl/REDO02.LOG
/oradata/orcl/REDO01.LOG
/oradata/orcl/sredo01.log
/oradata/orcl/sredo02.log
/oradata/orcl/sredo03.log
/oradata/orcl/sredo04.log

7 rows selected.

完成Standby Logfile的迁移。

以下两篇文章可用于该知识点的巩固:
《ALTER DATABASE CLEAR UNARCHIVED LOGFILE的使用》:
《Redo丢失的4种情况及处理方法》:

 注意:以上的操作可能在备库上无法完成,解决方法是,在主库完成Standby Logfile迁移之后,主库在MOUNT状态下创建新的for Standby Controlfile(alter database create standby controlfile as '/tmp/controlf.ctl'; ),将新的Standby Controlfile和Standby Logfile传递到相同的位置,恢复备库到一致状态,打开备库,开始应用日志即可。可以参考文章《Oracle Active Data Guard调整案例[2]》:

Data Guard备库一定要是一致的状态才能open read only打开,否者执行alter database recover managed standby database应用日志,恢复到一致性的状态,再open read only。

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