RAC数据恢复至单机环境
一、概括
随着越来越多的RAC环境，将RAC数据迁移至单机环境下的需求也随之增加，怎样才能更有效的迁移呢，方法有许多逻辑迁移（exp/expdp）、RMAN、DG、goldengate等，我们可根据自身环境及需求选择相应的迁移方式，下面简单介绍一下使用RMAN将RAC数据迁移至单机环境中的步骤。
二、 模拟环境：整套RAC环境无故宕机，暂无法恢复，我们将之前备份的数据进行恢复
将最近一次全备份文件上传至目标环境，并查看文件信息
/oracle/backup
[oracle@oradb1 backup]$ ls -lrt
总计 264312
-rw-r----- 1 oracle oinstall 132608 02-17 13:24 arch_0lp0ro84
-rw-r----- 1 oracle oinstall 19456 02-17 13:24 arch_0ip0ro4u
-rw-r----- 1 oracle oinstall 1114112 02-17 13:24 full_0kp0ro7v_1_1
-rw-r----- 1 oracle oinstall 269107200 02-17 13:24 full_0jp0ro50_1_
通过上述我们可以看到，归档文件有两个，由于是测试环境，数据量及备份信息较简单，数据文件也是两个，由此得知文件full_0kp0ro7v_1_1存放参数文件和控制文件。
设置环境变量
[oracle@oradb1 ~]$ vi ~/.bash_profile
修改参数为：export ORACLE_SID=racdb1
恢复spfile文件
[oracle@oradb1 backup]$ rman target /
Recovery Manager: Release 11.2.0.4.0 - Production on Mon Feb 17 11:37:45 2014
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
connected to target database (not started)
RMAN> startup force nomount;
startup failed: ORA-01078: failure in processing system parameters
LRM-00109: could not open parameter file '/oracle/db_1/dbs/initracdb1.ora'
starting Oracle instance without parameter file for retrieva l of spfile
Oracle instance started
Total System Global Area 1068937216 bytes
Fixed Size 2260088 bytes
Variable Size 281019272 bytes
Database Buffers 780140544 bytes
Redo Buffers 5517312 bytes
RMAN> restore spfile from '/oracle/backup/full_0kp0ro7v_1_1';
Starting restore at 17-FEB-14
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=19 device type=DISK
channel ORA_DISK_1: restoring spfile from AUTOBACKUP /oracle/backup/full_0kp0ro7v_1_1
channel ORA_DISK_1: SPFILE restore from AUTOBACKUP complete
Finished restore at 17-FEB-14
RMAN> restore spfile from '/oracle/backup/full_0kp0ro7v_1_1';
Starting restore at 17-FEB-14
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=19 device type=DISK
channel ORA_DISK_1: restoring spfile from AUTOBACKUP /oracle/backup/full_0kp0ro7v_1_1
channel ORA_DISK_1: SPFILE restore from AUTOBACKUP complete
Finished restore at 17-FEB-14
登录到数据库，生成pfile文件，并编辑，删除与集群即节点2相关参数，修改控制文件及其他目录路径，并根据需求创建相应目录（如闪回区、oracle基础目录）
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idle> create pfile from spfile;
File created.
创建spfile，并重启实例
idle> create spfile from pfile;
File created.
idle> show parameter pfile
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
spfile string
idle> show parameter spfile
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
spfile string
idle> shutdown abort
ORACLE instance shut down.
idle> startup nomount
ORACLE instance started.
Total System Global Area 534462464 bytes
Fixed Size 2254952 bytes
Variable Size 213911448 bytes
Database Buffers 314572800 bytes
Redo Buffers 3723264 bytes
idle> show parameter pfile
NAME TYPE VALUE
------------------------------------ ---------