一、在Oracle数据open状态下，用rman备份
rman备份必须在归档模式下
查看是否是归档模式
SQL> archivelog list;
修改为归档模式
shutdown immediate
startup mount
alter database archivelog;(alter database noarchivelog)
1、在第三台机器上用rman连接源数据库
rman target sys/sysdba@demo1
2、启动自动备份
RMAN> configure controlfile autobackup on;
3、备份
RMAN> backup database plus archivelog delete input format '/u01/rmanbackup/dup_%U';
4、查看备份情况
RMAN> list backup;
5、拷贝spfile和口令文件到dbs下，并建立init+实例名.ora
输入
db_name=实例名
例如：db_name='demo1'
6.把生成的rman备份拷贝到相应的目录
7.启动目标数据库到nomount状态
startup nomount
8.在连接主机上建立dup.txt
输入
run {
allocate auxiliary channel dup1 type disk;
duplicate database to demo1 spfile backup location '/u01/rmanbackup' nofilenamecheck
logfile
group 1 ('/u01/app/oracle/oradata/redo01_1.rdo','/u01/app/oracle/oradata/redo01_2.rdo') size 52428800,
group 2 ('/u01/app/oracle/oradata/redo02_1.rdo','/u01/app/oracle/oradata/redo02_2.rdo') size 52428800,
group 3 ('/u01/app/oracle/oradata/redo03_1.rdo','/u01/app/oracle/oradata/redo03_2.rdo') size 52428800;
}
9.用rman连接数据库
RMAN> connect auxiliary sys/sysdba@demo2
10.执行脚本
RMAN>@dup.txt
11.当执行出错时及某个进程不能启动时，执行
[oracle@localhost u01]$ ipcs
[oracle@localhost u01]$ ipcrm -s semid