我们在recover database时报一个错误：
RMAN-06054: media recovery requesting unknown archived log for thread 1 with sequence 149 and starting SCN of 3507749
这里是提醒恢复到一个未知的scn号。我们在备份时只有148号归档，149号还是online redo，所以没有copy过来，如果我们不指定recover的结束时间，最后就会提示我们上面的信息：RMAN-06054. 所以在alter database mount之后，通过set until scn或者set until time命令设置恢复到的scn号或时间，就可以避免这个错误。如：
RMAN> run{
set until sequence 149;
recover database;
}
executing command: SET until clause
Starting recover at 2016-05-12 23:27:34
using channel ORA_DISK_1
starting media recovery
media recovery complete, elapsed time: 00:00:00
Finished recover at 2016-05-12 23:27:
L、恢复完成之后，还有一个十分重要的工作要做，那就是恢复redo log files.如果源库的目录结构与新库的目录结构相同的话，在open resetlogs 时，会重新创建online redo log。但是现在redo log file文件的位置变了，open resetlogs时报如下错误：
RMAN> alter database open resetlogs; RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of sql statement command at 05/12/2016 23:37:46
ORA-00344: unable to re-create online log '/u01/app/oracle/oradata/scp/redo01.log'
ORA-27040: file create error, unable to create file
Linux-x86_64 Error: 2: No such file or directory
Additional information:
由于源库和目标库的路径不相同，oracle试图在原来旧的位置去创建redo log file，但是却发现目标库上不存在这个路径了.解决方法仍然是将旧文件的路径重置为新的路径,但是我们怎么知道源库redo log file文件的位置呢？因为数据库已经mount上了，直接执行查询：
RMAN> select group#,type,member from v$logfile; group# type MEMBER
--------------------------------------------------------------------------------
3 online /u01/app/oracle/oradata/scp/redo03.log
2 online /u01/app/oracle/oradata/scp/redo02.log
1 online /u01/app/oracle/oradata/scp/redo01.log
接下来我们将这些redo log file指定到新的文件位置：
RMAN> run{
ALTER DATABASE RENAME file '/u01/app/oracle/oradata/scp/redo01.log' TO '/home/OracleData/scp/redo01.log';
ALTER DATABASE RENAME file '/u01/app/oracle/oradata/scp/redo02.log' TO '/home/OracleData/scp/redo02.log';
ALTER DATABASE RENAME file '/u01/app/oracle/oradata/scp/redo03.log' TO '/home/OracleData/scp/redo03.log';
}
Statement processed
Statement processed
Statement processed
这个时候我们以resetlogs方式打开数据库，oracle报ora-00392的错误，
RMAN> alter database open resetlogs; RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of sql statement command at 05/13/2016 00:07:37
ORA-00392: log 2 of thread 1 is being cleared, operation not allowed
ORA-00312: online log 2 thread 1: '/home/OracleData/scp/redo02.log'
我们这个时候来查询一下redo log file的状态：
RMAN> select group#,sequence#,bytes,members,status from v$log;
GROUP# SEQUENCE# BYTES MEMBERS STATUS
---------- ---------- ---------- ---------- ----------------
1 0 52428800 1 CLEARING
3 0 52428800 1 CLEARING
2 0 52428800 1 CLEARING_CURRENT
以下是oracle的官方文档：
（1）CLEARING ---- Log is being re-created as an empty log after an ALTER DATABASE CLEAR LOGFILE statement.After the log is cleared, the status changes to UNUSED.
（2）CLEARING_CURRENT ----Current log is being cleared of a closed thread. The log can stay in this status if there is some failure in the switch such as an I/O error writing the new log header.
解决办法：
RMAN> alter database clear logfile group 2;
Statement processed
RMAN> select group#,sequence#,bytes,members,status from v$log;
GROUP# SEQUENCE# BYTES MEMBERS STATUS
---------- ---------- ---------- ---------- ----------------
1 0 52428800 1 CLEARING
3 0 52428800 1 CLEARING
2 0 52428800 1 CURRENT
M、最后用open resetlogs方式打开数据库，并执行一些日志切换。
RMAN> alter database open resetlogs;
Statement processed
RMAN> alter system switch logfile;
Statement processed
RMAN> alter system switch logfile;
Statement processed
RMAN> select group#,sequence#,bytes,members,status from v$log;
GROUP# SEQUENCE# BYTES MEMBERS STATUS
---------- ---------- ---------- ---------- ----------------
1 1 52428800 1 ACTIVE
2 2 52428800 1 ACTIVE
3 3 52428800 1 CURRENT
N、这还没有完，我们需要创建spfile文件、临时表空间和密码文件：
RMAN> alter tablespace temp add tempfile '/home/OracleData/scp/temp01.dbf' size 29m reuse autoextend on next 640k maxsize 32767m; Statement processed RMAN> create spfile from pfile; RMAN> host; [oracle@scpdb rmanbak]$ orapwd file='$ORACLE_HOME/dbs/orapwscp' password='abc123!@#' entries=3 关于密码文件，要注意文件名格式 orapw$ORACLE_SID (注意不需要后缀名),具体请参照Oracle官方文档：
https://docs.oracle.com/cd/B28359_01/server.111/b28310/dba007.htm
至此，利用rman恢复数据库到不同主机的操作就全部完成了，记得马上做一次RMAN的全备！！！