RAC数据库恢复到单实例数据库的基本步骤如下：
a.准备单实例服务器，pfile文件，启动到nomount
b.备份rac数据库
c.将备份文件拷贝到单实例服务器
d.在单实例服务器上还原、恢复
e.resetlogs打开数据库
f.rename redo文件名
g.disable thread 2并删除其redo组
h.增加temp临时表空间数据文件
i.删除不必要的undo表空间
业务需要（比如，
测试备份）将RAC数据库通过备份恢复到单实例服务器；下面是实际操作步骤；测试环境：RHEL4u7、oracle 10gR2、ASM、2节点，单实例服务器：RHEL4u7、oracle 10gR2、文件系统；在测试环境下，RAC 数据库文件都在asm时，在rename file操作时会遇到了
BUG问题，最后的恢复时则需要重建控制文件；上面介绍的步骤是指没有BUG的情况的操作；
另外，备份、拷贝的环节就请参考其他文档，就不介绍了，下面从第4步在单实例服务器上还原、恢复与打开开始介绍；
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RMAN> startup nomount
RMAN> restore controlfile to '/app/oracle/oradata/ctl01.dbf' from '/app/oracle/backup/ctl_23_1_855331400';
RMAN> run{startup mount;
set until sequence 870 thread 1;
set newname for datafile 1 to '/app/oracle/oradata/system.257.779207027';
set newname for datafile 3 to '/app/oracle/oradata/sysaux.262.779207043';
set newname for datafile 4 to '/app/oracle/oradata/users.260.779207053';
set newname for datafile 2 to '/app/oracle/oradata/undotbs1.264.779207043';
set newname for datafile 15 to '/app/oracle/oradata/pptest_tbs.282.793979093';
set newname for datafile 5 to'/app/oracle/oradata/undotbs2.268.779207507';
set newname for datafile 8 to'/app/oracle/oradata/tbs_p3w.271.780396123';
set newname for datafile 9 to'/app/oracle/oradata/tbs_p4w.274.780396125';
set newname for datafile 6 to'/app/oracle/oradata/tbs_p1w.270.780396121';
set newname for datafile 7 to'/app/oracle/oradata/tbs_p2w.273.780396123';
set newname for datafile 14 to'/app/oracle/oradata/pptest_tbs.279.781454807';
restore database;
switch datafile all;
recover database;
}
sys@racdb3> alter database rename file '+DG/racdb/onlinelog/group_1.263.779207025' to '/app/oracle/oradata/redo1.log';
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rename 完所有redo文件后，即可resetlogs打开数据库；但是，实际操作中遇到bug7207932：Rman Restore From RAC ASM To Single Instance Non ASM Fails With ORA-00600 [kgeade_is_0] (文档 ID 1146703.1)
Bug 7207932 ORA-600 [KGEADE_IS_0] WHEN RENAMING A FILE FROM ASM TO FS
要想绕开的方法则是重建控制文件后，再打开数据库
sys@racdb3> alter database backup controlfile to trace as '/tmp/ctl.trc' reuse resetlogs;
打开trace文件，修改里面的logfile部分信息；然后重启数据库到nomount状态；
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sys@racdb3> shutdown immediate
SQL> STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "RACDB" RESETLOGS ARCHIVELOG
MAXLOGFILES 50
MAXLOGMEMBERS 2
MAXDATAFILES 2000
MAXINSTANCES 8
MAXLOGHISTORY 292
LOGFILE
GROUP 1 '/app/oracle/oradata/group_1.263.779207025' SIZE 10M,
GROUP 2 '/app/oracle/oradata/group_2.259.779207027' SIZE 10M,
GROUP 3 '/app/oracle/oradata/group_3.258.779207027' SIZE 10M
DATAFILE
'/app/oracle/oradata/system.257.779207027',
'/app/oracle/oradata/undotbs1.264.779207043',
'/app/oracle/oradata/sysaux.262.779207043',
'/app/oracle/oradata/users.260.779207053',
'/app/oracle/oradata/undotbs2.268.779207507',
'/app/oracle/oradata/tbs_p1w.270.780396121',
'/app/oracle/oradata/tbs_p2w.273.780396123',
'/app/oracle/oradata/tbs_p3w.271.780396123',
'/app/oracle/oradata/tbs_p4w.274.780396125',
'/app/oracle/oradata/pptest_tbs.279.781454807',
'/app/oracle/oradata/pptest_tbs.282.793979093'
CHARACTER SET ZHS16GBK
;
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创建完成后，用backup controlfile进行恢复；
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sys@racdb3> RECOVER DATABASE USING BACKUP CONTROLFILE until cancel;
sys@racdb3>ALTER DATABASE ADD LOGFILE THREAD 2
GROUP 4 '/app/oracle/oradata/group_4.265.779207453' SIZE 10M REUSE,
GROUP 5 '/app/oracle/oradata/group_5.266.779207459' SIZE 10M REUSE,
GROUP 6 '/app/oracle/oradata/group_6.267.779207467' SIZE 10M REUSE;
sys@racdb3> alter database open resetlogs;
成功resetlogs打开后，还需要做一些去thread 2的操作；
sys@racdb3> alter database disable thread 2;
sys@racdb3> alter database drop logfile group 4;
alter database drop logfile group 4
*
ERROR at line 1:
ORA-00350: log 4 of instance UNNAMED_INSTANCE_2 (thread 2) needs to be archived
ORA-00312: online log 4 thread 2: '/app/oracle/oradata/RACDB/onlinelog/o1_mf_4_9ym2kvgf_.log'
sys@racdb3> alter database clear unarchived logfile group 4;
sys@racdb3> alter tablespace temp add tempfile '/app/oracle/oradata/temp01.dbf' size 10M reuse;
Tablespace altered.
sys@racdb3> drop tablespace undotbs2 including contents and datafiles;
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最新内容请见作者的GitHub页：http://qaseven.github.io/
