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如果客户主库的归档日志没有删除，那么备库启动后会自动同步最近的日志文件，保持与主库的同步；很明显，上面客户归档日志随着备份完成而清理，导致备库无法自动恢复。
下面模拟该场景的故障恢复。
（一）测试环境主备# 主、备库版本SQL> select * from v$version;BANNER--------------------------------------------------------------------------------Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit ProductionPL/SQL Release 11.2.0.4.0 - ProductionCORE 11.2.0.4.0 ProductionTNS for Linux: Version 11.2.0.4.0 - ProductionNLSRTL Version 11.2.0.4.0 - Production#主库测试环境，产生较多归档日志sys@ORCL> create table dgr tablespace tbs_baiyang as select * from all_objects;sys@ORCL> alter system switch logfile;#备库同步状态查询SQL> select archived,max(sequence#),applied from v$archived_log group by archived,applied;ARC MAX(SEQUENCE#) APPLIED--- -------------- ---------YES 81 IN-MEMORYYES 80 YESSQLL> select count(*) from dgr; COUNT(*)---------- 84431# 目前主备库同步正常
（二）模拟故障环境
# 关闭备库SQL> alter database recover managed standby database cancel;SQL> shutdown immediate# 主库执行大量更新操作，以产生大量归档日志sys@ORCL> archive log listDatabase log mode Archive ModeAutomatic archival EnabledArchive destination /u01/app/oracle/oradata/orcl/archivelogOldest online log sequence 83Next log sequence to archive 85Current log sequence 85sys@ORCL> insert into dgr select * from dgr;84431 rows created.sys@ORCL> insert into dgr select * from dgr;168862 rows created.sys@ORCL> insert into dgr select * from dgr;337724 rows created.sys@ORCL> update dgr set object_id = 11;675448 rows updated.sys@ORCL> commit;Commit complete.sys@ORCL> archive log list;Database log mode Archive ModeAutomatic archival EnabledArchive destination /u01/app/oracle/oradata/orcl/archivelogOldest online log sequence 93Next log sequence to archive 95Current log sequence 95# 备份数据库RMAN> backup database;# 删除新生成归档日志文件cd /u01/app/oracle/oradata/orcl/archivelog$mkdir bak$mv 1_9* bak/# 打开备库SQL> startup mountSQL> select current_scn,database_role,open_mode from v$database;CURRENT_SCN DATABASE_ROLE OPEN_MODE----------- ---------------- -------------------- 3730534 PHYSICAL STANDBY MOUNTED# 开启日志应用报错 SQL> alter database recover managed standby database disconnect from session using current logfile;alter database recover managed standby database disconnect from session using current logfile*ERROR at line 1:ORA-01153: an incompatible media recovery is active#查看下目前的日志应用状态，仍有新的归档日志传输到备库，但无法应用SQL> select archived,max(sequence#),applied from v$archived_log group by archived,applied;ARC MAX(SEQUENCE#) APPLIED--- -------------- ---------YES 97 NOYES 89 YES# 查看下是否有gap产生，少了5个日志文件，正式刚才删除的SQL> select * from v$archive_gap; THREAD# LOW_SEQUENCE# HIGH_SEQUENCE#---------- ------------- -------------- 1 90 94 # 以上就是模拟故障发生的步骤
（三）恢复前的准备
以RMAN增量备份的方式恢复备库的过程中，需要重建备库的控制文件，势必需要了解当前备库的数据库文件、日志文件归属；如果主备文件目录保持一致，那么可以跳过这一步# 日志目录SQL> set linesize 300SQL> col MEMBER for a60SQL> select type,member from v$logfile;TYPE MEMBER------- ------------------------------------------------------------ONLINE /u01/app/oracle/oradata/standby/redo03.logONLINE /u01/app/oracle/oradata/standby/redo02.logONLINE /u01/app/oracle/oradata/standby/redo01.logSTANDBY /u01/app/oracle/oradata/standby/standbylog/redo11.logSTANDBY /u01/app/oracle/oradata/standby/standbylog/redo12.logSTANDBY /u01/app/oracle/oradata/standby/standbylog/redo13.logSTANDBY /u01/app/oracle/oradata/standby/standbylog/redo14.log# 数据文件目录SQL> select name from v$datafile;NAME--------------------------------------------------------------------------------/u01/app/oracle/oradata/standby/datafile/system01.dbf/u01/app/oracle/oradata/standby/datafile/sysaux01.dbf/u01/app/oracle/oradata/standby/datafile/undotbs01.dbf/u01/app/oracle/oradata/standby/datafile/users01.dbf/u01/app/oracle/oradata/standby/datafile/tbs_baiyang.dbf/u01/app/oracle/oradata/standby/datafile/lxx2.dbf# 查询当前备库的SCNSQL> select current_scn,database_role,open_mode from v$database;CURRENT_SCN DATABASE_ROLE OPEN_MODE----------- ---------------- -------------------- 3730534 PHYSICAL STANDBY MOUNTED# 主库再进行一些更新操作sys@ORCL> update dgr set object_id = 11;675448 rows updated.sys@ORCL> commit;Commit complete.
（四）增量备份主库，及备份主库控制文件
# 增量备份RMAN> run{allocate channel c1 device type disk;backup incremental from scn 3730534 database format '/oradata/ora_scn_%U.bak'; release channel c1;}RMAN> BACKUP CURRENT CONTROLFILE FOR STANDBY FORMAT '/oradata/ctl_20181213.bak';# 将备份集传到备库scp *.bak 172.16.8.123:/oradata/ （五）恢复备库
# 首先使用增量备份恢复数据库RMAN> catalog start with '/oradata/';RMAN> recover database noredo;……channel ORA_DISK_1: restored backup piece 1channel ORA_DISK_1: restore complete, elapsed time: 00:00:07Finished recover at 13-DEC-18# 关闭并重新备库至nomount状态，此时控制文件需要恢复（为什么）SQL> startup nomount# 使用主库控制文件备份恢复备库控制文件RMAN> RESTORE STANDBY CONTROLFILE FROM '/oradata/ctl_20181213.bak';Starting restore at 13-DEC-18using channel ORA_DISK_1channel ORA_DISK_1: restoring control filechannel ORA_DISK_1: restore complete, elapsed time: 00:00:01output file name=/u01/app/oracle/oradata/standby/control01.ctloutput file name=/u01/app/oracle/fast_recovery_area/standby/control02.ctlFinished restore at 13-DEC-18#启动数据库到mount状态SQL> alter database mount;
（六）控制文件恢复后，数据和日志文件路径要是和备库现有不同，可以使用在线命令rename数据文件，重建日志文件，主要是standby 日志
…… ALTER DATABASE RENAME file '/u01/app/oracle/oradata/orcl/datafile/tbs_baiyang.dbf' to '/u01/app/oracle/oradata/standby/datafile/tbs_baiyang.dbf';……SQL> alter database add standby logfile group 24 '/u01/app/oracle/oradata/standby/standby24.log' size 50m;……SQL> alter database drop standby logfile group 14;……
（七）这时打开数据库、打开日志实时应用进程
SQL> alter database open;SQL> alter database recover managed standby database disconnect from session using current logfile;SQL> select archived,max(sequence#),applied from v$archived_log group by archived,applied;ARC MAX(SEQUENCE#) APPLIED--- -------------- ---------YES 102 IN-MEMORYYES 101 YESSQL> select count(*) from dgr; COUNT(*)---------- 675448 SQL> select count(*) from dgr where object_id=11 ; COUNT(*)---------- 675448
为避免发生类似情况，（1）归档文件保留策略要尽可能的长，最好不要随着备份完成而删除（2）可以配置归档的备份策略，备份后可以删除归档，有需要从备份归档中还原
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