How to restore and recover a database from an RMAN backup. (Doc ID 881395.1)

Posted 2020-11-24 zylong-sys

APPLIES TO:

Oracle Database - Enterprise Edition - Version 10.1.0.2 to 11.2.0.2 [Release 10.1 to 11.2]
Oracle Database - Enterprise Edition - Version 11.2.0.4 to 11.2.0.4 [Release 11.2]
Oracle Database - Enterprise Edition - Version 11.2.0.3 to 11.2.0.3 [Release 11.2]
Oracle Database - Enterprise Edition - Version 12.1.0.1 to 12.1.0.1 [Release 12.1]
Oracle Database Cloud Schema Service - Version N/A and later
Information in this document applies to any platform.
***Checked for relevance on 21-AUG-15 ***

GOAL

The following note will guide a DBA through the process of restoring and recovering a database from an RMAN backup.  It will assist in a complete database restore.
以下说明将指导DBA通过RMAN备份还原和恢复数据库的过程。它将帮助完成完整的数据库还原
Assumption  假设
- A valid backup of the database is accessible.  可访问数据库的有效备份
- Required archive logs* to recover the database are available and accessible.  恢复数据库所需的存档日志*可用且可访问。
* Archive logs required are those generated from the start time of the backup until the completion of the backup if an online backup was performed. 

所需的存档日志是从备份开始时间到备份完成（如果执行了在线备份）生成的日志

If you need to perform restore/recovery on a different host for a backup taken on another host, also refer:

如果您需要在另一台主机上执行还原/恢复以在另一台主机上进行备份，请参考

Note 419137.1 How To Restore Rman Backups On A Different Node When The Directory Structures Are Different

SOLUTION

How to restore a complete database from an RMAN backup  如何从RMAN备份还原完整的数据库

This note assumes an RMAN catalog is not available. The use of a catalog is optional in this scenario as the backup information is available in the controlfile.

本说明假定RMAN目录不可用。在这种情况下，使用目录是可选的，因为控制文件中提供了备份信息

Prior to restoring a database you must ensure you have a valid RMAN backup.

在还原数据库之前，必须确保您具有有效的RMAN备份。
In this example we will assume all files are required to be restored:

在此示例中，我们假定需要还原所有文件：
* Datafiles
* Controlfiles
* Archivelogs (In order to perform recovery)

Online redo logs and temp files are recreated automatically by RMAN when a resetlogs is issued. Online redo logs and temp files are not backed up by RMAN

发出重置日志时，RMAN将自动重新创建联机重做日志和临时文件。RMAN不备份联机重做日志和临时文件

Step 1:  Identify controlfile backup to restore  确定要还原的控制文件备份

Note: If  you do not need to restore a controlfile proceed to step 3.  如果不需要还原控制文件，请继续执行 step 3

* Locate the RMAN backup you wish to restore.  找到要还原的RMAN备份。
* These files should be located in the directory where they were backed up to.  这些文件应位于它们备份到的目录中。
* If you have the RMAN backup log available this will also be of assistance. 如果您有可用的RMAN备份日志，这也将有所帮助。

Within the RMAN backup log you will see the controlfile is backed up last the the piece handle is shown. 

在RMAN备份日志中，您将看到控制文件最后备份，并且显示了片段句柄
....
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 2009/01/01 12:00:00
channel ORA_DISK_1: finished piece 1 at 2009/01/01 12:00:02
piece handle=/<FRA path>/o1_mf_ncsnf_TAG20090506T11_501tr0h7_.bkp tag=TAG20090506T11 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02

If you do not have an RMAN backup log simply locate the last file RMAN backed up.  This should contain the controlfile backup.

如果您没有RMAN备份日志，只需找到备份的RMAN上一个文件即可。这应该包含控制文件备份。

Step 2:  Restore the controlfile

2a) If you DO NOT have a spfile.

If you do have an spfile or init.ora move to Step 2b  如果您有spfile或init.ora，请转到步骤2b

If you do not have a valid spfile or init.ora RMAN has the ability to nomount an instance without the requirement of a spfile. This will allow you to restore your spfile from a valid backup.

如果您没有有效的spfile或init.ora，RMAN可以在不需要spfile的情况下卸载实例。 这将允许您从有效备份中还原spfile。

% rman target /

RMAN> startup nomount force;

 

You will see this message:  您将看到以下消息：
..
starting Oracle instance without parameter file for retrieval of spfile

启动不带参数文件的Oracle实例以检索spfile
..
At this point you can restore the spfile:  此时，您可以还原spfile：

RMAN> restore spfile from ‘/<FRA path>/o1_mf_ncsnf_TAG20_501tr0h7_.bkp‘;

RMAN> shutdown immediate;

 

Once the spfile has been successfully restored proceed to Step 2b.  

成功还原spfile后，请继续执行步骤2b。

2b)

SQL> startup nomount;

 

Following the successful nomount of the instance you are ready to restore the controlfile;  成功执行完实例之后，您就可以恢复控制文件了。
NOTE: The controlfile will be restored to the following location:
注意：控制文件将还原到以下位置：

SQL> show parameter control_files

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_files string /<oradata path>/control01.ctl

 

% rman target /

 

You will see the message:  您将看到以下消息：

connected to target database: V11 (not mounted)

RMAN> restore controlfile from ‘/<FRA path>/o1_mf_ncsnf_TAG20090506T113947_501tr0h7_.bkp‘;

Starting restore at 2009/05/11 11:01:26
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=151 device type=DISK

channel ORA_DISK_1: restoring control file
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
output file name=/<oradata path>/control01.ctl
Finished restore at 2009/05/11 11:01:27

In this example the controlfile has been restored to ‘/<oradata path>/control01.ctl‘

Step 3:  Restore and recover the database

Your next task is to restore the database and perform recovery.  Mount the database now that the controlfile has been restored:

下一个任务是还原数据库并执行恢复。 现在已经恢复了控制文件，请装入数据库：

RMAN> alter database mount;

 

Now you have two options for recovery.   现在，您有两个恢复选项。

1) Full/Complete recovery.  完全恢复
2) Point In Time Recovery (PIT)  基于时间点的不完全恢复

In both examples it is assumed that all archivelogs are available to perform the recovery.

在两个示例中，均假定所有存档日志都可用于执行恢复。

Full recovery
==========

To Perform a full restore and recovery.

run{
restore database;
recover database;
alter database open resetlogs;
}

　

If you performed a complete recovery with current controlfile and online redologs in place, you might get below error when opening the database with resetlogs:
如果使用当前的控制文件和联机重做日志执行了完全恢复，则在使用复位日志打开数据库时，可能会遇到以下错误：
ORA-01139: RESET LOGS option only valid after an incomplete database recovery
At this point simply open the database without resetlogs option.

此时，只需打开不带resetlogs选项的数据库即可。

PITR Recovery
===========

Point-In-Time Recovery (PITR) would be used if you have decided to restore a database to a particular point in time. This may be warranted for a hardware fault or if you are aware of a database corruption that occured at a certain date/time.
如果您决定将数据库还原到特定的时间点，则将使用时间点恢复（PITR）。 如果发生硬件故障，或者您知道在特定日期/时间发生数据库损坏，则可能需要这样做。

run{
set until time "to_date(‘Aug 16 2014 10:30:00‘,‘Mon DD YYYY HH24:MI:SS‘)";
restore database;
recover database;
sql ‘alter database open resetlogs‘;
}

　　

NOTE: The above scripts may be altered to allocate more channels. Good practice would be to review the backup log and use the same number of channels for restore as that used by the backup.  注意：可以更改以上脚本以分配更多通道。 良好的做法是查看备份日志，并使用与备份所使用的相同数量的通道进行还原。

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REFERENCES

NOTE:419137.1 - How To Restore Rman Backups On A Different Node When The Directory Structures Are Different