Checklist for an RMAN Restore (Doc ID 1554636.1)
APPLIES TO:
Oracle Database - Enterprise Edition - Version 10.2.0.1 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Information in this document applies to any platform.
GOAL
Prior to performing an RMAN restore, there are certain actions you can take to ensure its success. Rather than running a restore for hours only to find that it failed due to something avoidable in the first place, like a missing backuppiece, it would be better to get the environment fully prepared upfront. 在执行 RMAN restore 之前，您可以采取某些措施来确保其成功。与其运行 restore 花几个小时才能发现它最初是由于某些可避免的事情（例如缺少备份件）而失败，不如为恢复环境做好充分的准备。
A lot of time and confusion can be saved if we have a check list to work with first. 如果我们首先有一个检查清单，可以节省很多时间和混乱。
SOLUTION
1) Check the Operating System and RDBMS Version 检查操作系统和RDBMS版本
Ideally you should be restoring to the same operating system version and RDBMS Version. If restoring to a different operating system you may need to covert between the Endians.
理想情况下，您应该还原到相同的操作系统版本和RDBMS版本。如果还原到其他操作系统，则可能需要在Endians(字节)之间进行转换
If restoring to a higher version of the RDBMS you need to perform an upgrade before the database can be open for use:
如果还原到更高版本的RDBMS，则需要执行升级，然后才能打开数据库以供使用
Restoring a database to a higher patchset (Doc ID 558408.1)
The combinations of operating systems and RDBMS can be quite complex. See the following note for further details:
操作系统和RDBMS的组合可能非常复杂。有关更多详细信息，请参见以下 note：
Frequently Asked Questions about Restoring Or Duplicating Between Different Versions And Platforms (Doc ID 369644.1)
2) Confirm Space Requirements 确认空间要求
As your database grow and shrink, the space usage may vary. Confirm the directories/diskgroup, and its space requirements using the REPORT SCHEMA command.
随着数据库的增长和收缩，空间使用情况可能会有所不同。使用 REPORT SCHEMA 命令确认目录/磁盘组及其空间要求
RMAN> run {
set until time "to_date('2013 JUN 11 15:31','YYYY MON DD HH24:MI')";
report schema;
}
executing command: SET until clause
using target database control file instead of recovery catalog
Report of database schema for database with db_unique_name <db_unique_name>
List of Permanent Datafiles
===========================
File Size(MB) Tablespace RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1 830 <tablespace name> *** /<db file path>/<db file name>.dbf
2 980 <tablespace name> *** /<db file path>/<db file name>.dbf
3 205 <tablespace name> *** /<db file path>/<db file name>.dbf
4 100 <tablespace name> *** /<db file path>/<db file name>.dbf
5 345 <tablespace name> *** /<db file path>/<db file name>.dbf
6 100 <tablespace name> *** /<db file path>/<db file name>.dbf
From the above we can see the tablespace, the datafiles and space requirements. The datafile's directories and diskgroups must pre-exist and have sufficient space to hold the datafiles. Otherwise you need to use the SET NEWNAME to restore to an alternate location that has the permission and space availability.
从上面我们可以看到表空间，数据文件和空间需求。数据文件的目录和磁盘组必须预先存在，并具有足够的空间来容纳数据文件。否则，您需要使用 SET NEWNAME 还原到具有权限和空间可用性的备用位置。
Note: you may also need space in the archive log destination if the required archivelogs will be also be restored from their backuppieces
注意：如果还从备份文件中还原了所需的归档日志，则您可能还需要在归档日志目标中留出空间
3) Backup Scripts and Logs
In preparation for the restore, have the backup scripts and logs handy. The output from an RMAN command will be displayed to the standard output by default. If running interactively it will be displayed on your screen. You can always spool the output using the command:
在准备还原时，请准备好备份脚本和日志。默认情况下，RMAN命令的输出将显示为标准输出。如果以交互方式运行，它将显示在屏幕上。您始终可以使用以下命令 spool 输出
RMAN> SPOOL TRACE TO X.OUT SET ECHO ON # place the rest of your rman commands here --将其余的rman命令放在这里 SPOOL TRACE OFF;
An RMAN backup log will help us confirm the backup's success/failure, what files were actually backed up, and timings such as the start and end of backup, and elapsed times.
RMAN 备份日志将帮助我们确认备份的成功/失败，实际备份了哪些文件以及诸如备份开始和结束的时间以及经过的时间。
If restoring to the same host, consider temporarily turning off your scheduled backup jobs first. Since the database is being restored we do not want backups jobs to run, nor archivelogs needed for recovery to be removed.
如果要还原到同一主机，请考虑首先暂时关闭计划的备份作业。由于正在还原数据库，因此我们不希望运行备份作业，也不想删除恢复所需的归档日志
4) Be Mindful of the FRA 注意 FRA
If using a restored controlfile, RMAN will perform an implicit crosscheck and cataloging of the FRA if the FRA is in use. This may add to your restore time, and can sometimes cause incarnation issues if the database has under gone a few resetlogs.
如果使用还原的控制文件，则在使用 FRA 的情况下，RMAN 将对 FRA 执行隐式 crosscheck(交叉检查) 和 cataloging。这可能会增加您的还原时间，并且如果数据库缺少一些重置日志，有时可能会导致 incarnation(化身)问题。
If you don't need the files in the FRA, you can either remove the files from the FRA or just disable it during the restore, and re-enable it afterwards.
如果不需要 FRA 中的文件，则可以从 FRA 中删除文件，也可以在还原过程中将其禁用，然后再重新启用它。
RMAN restore hangs with "Starting implicit crosscheck" & "cataloging files" (Doc ID 1489027.1)
5) Obtain a Summary of the RMAN Backup 获取RMAN备份信息
To give us a quick overview of the backups taken: 为了让我们快速了解已执行的备份
RMAN> spool trace to <spool file name>; set echo on; list incarnation of database; list backup summary; list backup of datafile 1; list copy of datafile 1; spool trace off;
6) Previewing the Restore and Recovery 预览 Restore and Recovery
You can apply RESTORE ... PREVIEW to any RESTORE operation to create a detailed list of every backup to be used in the requested RESTORE operation, and the necessary target SCN for recovery after the RESTORE operation is complete. This command accesses the RMAN repository to query the backup metadata, but does not actually read the backup files to ensure that they can be restored.
您可以应用 RESTORE ... PREVIEW任何RESTORE操作，以创建要在请求的RESTORE操作中使用的每个备份的详细列表，以及RESTORE操作完成后恢复所需的目标SCN 。此命令访问RMAN存储库以查询备份元数据，但实际上并不读取备份文件
Blockrecovery can also be previewed:
RMAN> blockrecover corruption list preview;
The entire restore can be previewed in one command: 可以使用一个命令预览整个还原
RMAN> run {
set until time "to_date('2013 JUN 11 15:31','YYYY MON DD HH24:MI')";
restore controlfile database preview;
}
A restore preview will list all backups required for the entire restore and recovery operation. From this list you can then go ahead and confirm that the backuppieces are physically available on disk or tape before performing the actual restore.
一个 restore preview 将列出整个还原和恢复操作所需的所有备份。然后，从该列表中可以继续进行操作，并在执行实际还原之前确认备份块在磁盘或磁带上是否物理可用
Useful items from the restore preview: 还原预览中的有用项目
RMAN> run {
2> set until time "to_date('2014 MAY 02 11:22','YYYY MON DD HH24:MI')";
3> restore database preview;
4> }
...
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ --------------------
266 Incr 0 **[1]** 1.49G**[2]** DISK[3] 00:01:31[4] 02 MAY 2014 11:21:57 [5]
BP Key: 268 Status: AVAILABLE[6] Compressed: NO[7] Tag: <TAG NAME>
Piece Name: /<backup piece path>/<backuppiece name>[8]
List of Datafiles in backup set 266 [9]
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- -------------------- ----
1 0 Incr 53204035 02 MAY 2014 11:20:27 /<db file path>/<db file name>
4 0 Incr 53204035 02 MAY 2014 11:20:27 /<db file path>/<db file name>
7 0 Incr 53204035 02 MAY 2014 11:20:27 /<db file path>/<db file name>
9 0 Incr 53204035 02 MAY 2014 11:20:27 /<db file path>/<db file name>
...
List of Archived Logs in backup set 268
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- -------------------- ---------- ---------
1 317 53204027 02 MAY 2014 11:20:25 53204084 02 MAY 2014 11:22:03
Media recovery start SCN is 53204027
Recovery must be done beyond SCN 53204036 to clear datafile fuzziness[10]
Finished restore at 02 MAY 2014 11:24:07
[1] This is an incremental level 0 backup
[2] The backuppiece is 1.49G in size
[3] This is a backup to DISK rather than tape
[4] The backuppiece took 1 minute and 31 seconds to backup
[5] The time when this backuppiece completed
[6] The backuppiece is available for use according to the RMAN repository
[7] This is NOT a compressed backup
[8] This is the backuppiece. It must exist on disk for use:
$ ls -l <Backup location>
-rw-r-----. 1 oracle oinstall 1601011712 May 2 11:21 /<Backup location>/<backuppiece name>
[9] the datafiles contained in this backuppiece
[10] this is just informational message. It simply telling you that the SET UNTIL must reflect a time/SCN that is beyond this value before the database can be opened
a) Preview the Controlfile Restore
If perform a database restore to a point in time in the past, you should also restore the controlfile as it will reflect the database structure at the time. This is especially important if there are tablespaces or datafiles being added or dropped over the database's lifetime.
An example of a controlfile restore preview:
RMAN> run {
set until time "to_date('Jun 18 2013 08:00:00','Mon DD YYYY HH24:MI:SS')";
restore controlfile preview;
}
using target database control file instead of recovery catalog
..
executing command: SET until clause
Starting restore at 06/18/2013 22:28:04
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -------------------
52857 Full 19.00M SBT_TAPE 00:00:09 06/18/2013 04:02:04
BP Key: 52857 Status: AVAILABLE Compressed: NO Tag: <tag name>
Handle: <backuppiece name [1] Media: <media name> [2]
Control File Included: Ckp SCN: 238614135722 Ckp time: 06/18/2013 04:01:55
List of Backup Sets
===================
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
52858 430.50M SBT_TAPE 00:00:36 06/18/2013 09:01:10
BP Key: 52858 Status: AVAILABLE Compressed: NO Tag: <tag name>
Handle: Handle: <backuppiece name [1] Media: <media name>[2]
List of Archived Logs in backup set 52858
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ---------- ---------
1 14822 238614135104 06/18/2013 04:00:28 238614215594 06/18/2013 08:40:24 [3]
validation succeeded for backup piece
Media recovery start SCN is 238614135722
Recovery must be done beyond SCN 238614135722 to clear datafile fuzziness
validation succeeded for backup piece
Finished restore at 06/18/2013 22:28:13
released channel: dev_0
[1] "Handle" is the backuppiece name
[2] Media is the lable given to the tape
[3] This is the achivelog needed to recover this controlfile
That is, you need to ensure that the backuppiece [1] on tape [2] is loaded and ready for use
b) Preview the Database Restore
An example of a point in time restore preview command:
RMAN> spool trace to res.prev
run {
set until time "to_date('2013 JUN 11 15:31','YYYY MON DD HH24:MI')";
restore database preview;
}
spool trace off
From the preview output, look for errors such as "datafile x not processed"; "data file x will be created", "no backup of archived log"; "file x is excluded from whole database backup"; "could not locate pieces of backup set key x". etc.
RMAN-06026: some targets not found - aborting restore
RMAN-06023: no backup or copy of datafile 4 found to restore
RMAN-06100: no channel to restore a backup or copy of datafile 18
no channel to restore a backup or copy of log thread 1 seq 186 lowscn 609321
Readonly datafiles
In 10g READ ONLY datafiles will only be restored if using CHECK READONLY. Whereas in 11g the read only datafiles are restored by default, except if you use SKIP READONLY.
datafile 29 not processed because file is read-only
If restoring to a new host, do you want the read only datafile to be restored or not?
Datafile will be created rather than restored
During the preview, if you get the error message below:
then you should confirm why there seems to be no backup for this datafile. If you have all archivelogs from the time of this datafile creation to complete the recovery then it should be ok. Otherwise you should find out RMAN is not using the backup. Is there even a backup to use?
RMAN> list backup of datafile 25;
RMAN> list copy of datafile 25;
If you get the message that file 1 will be created then there is a problem. File 1, which is the system datafile, cannot be recreated automatically from the restore process. It must be restored from a backup.
Missing archivelog
Recovery will need this archivelog so you need to find the backuppiece containing the archivelog, or the archivelog itself
RMAN-06100 No Channel to Restore a Backup or Copy
Often this is a sign that the appropriate channels have not been allocated to perform the restore. For example, if the backups are on tape, ensure that an SBT channel is allocated.
RMAN-06100 during restore/duplicate (Doc ID 1615996.1)
c) Recovery Preview
Recovery Preview is only available from 11g onwards.
Once the database is restored, mounted, then the recovery can also be previewed:
set until time "to_date('2013 JUN 11 15:31','YYYY MON DD HH24:MI')";
recover database preview;
}
7) How Long will the Restore Take?
If restoring to the same host, and all loads being equal, then a restore operation should take a similar time as the backup. Look at Elapsed Time from the restore preview:
------- ---- -- ---------- ----------- ------------ --------------------
258 Full 1.49G DISK 00:01:33 02 MAY 2014 10:14:55
8) Validating the Restore
As an alternative to RESTORE ... PREVIEW, you can use the RESTORE ... VALIDATE HEADER command. In addition to listing the files needed for restore and recovery, the RESTORE ... VALIDATE HEADER command validates the backup file headers to determine whether the files on disk or in the media management catalog correspond to the metadata in the RMAN repository.
When planning your restore and recovery operation, use RESTORE ... PREVIEW or RESTORE ... VALIDATE HEADER to ensure that all required backups are available or to identify situations in which you may want to direct RMAN to use or avoid specific backups.
RMAN> restore database validate;
Starting restore at 26 JUN 2013 14:41:23
using channel ORA_DISK_1
using channel ORA_DISK_2
skipping datafile 6; already restored to file <db file path>/<db file name>
datafile 7 will be created automatically during restore operation
channel ORA_DISK_1: starting validation of datafile backup set
channel ORA_DISK_2: starting validation of datafile backup set
channel ORA_DISK_1: reading from backup piece /< backuppiece path>/<backuppiece name>
channel ORA_DISK_2: reading from backup piece /< backuppiece path>/<backuppiece name>
channel ORA_DISK_2: ORA-19870: error while restoring backup piece /< backuppiece path>/<backuppiece name>
ORA-19505: failed to identify file "/< backuppiece path>/<backuppiece name>"
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
channel ORA_DISK_1: piece handle=/< backuppiece path>/<backuppiece name> tag=<tag name>
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: validation complete, elapsed time: 00:00:03
failover to previous backup
datafile 7 will be created automatically during restore operation
channel ORA_DISK_1: scanning datafile copy /<datafile copy path>/<datafile copy name>
channel ORA_DISK_2: scanning datafile copy /<datafile copy path>/<datafile copy name>
failover to previous backup
datafile 7 will be created automatically during restore operation
Finished restore at 26 JUN 2013 14:41:53
RMAN> list backuppiece '/<backuppiece path>/<backuppiece name>';
List of Backup Pieces
BP Key BS Key Pc# Cp# Status Device Type Piece Name
------- ------- --- --- ----------- ----------- ----------
43 43 1 1 AVAILABLE DISK /<backuppiece path>/<backuppiece name>
From the above we can see that the backuppiece is missing from disk even though it is listed as AVAILABLE for use. So you need to locate this backuppiece before performing the actual restore.
Additional Info:
(Doc ID 1481151.1) RMAN "restore... Validate [header]" Lists Full Or L0 Backups Only
9) Gotchas
NOLOGGING
Be mindful of NOLOGGING operations - was the original database in FORCE LOGGING mode? Otherwise, do you have nologging operations that may result in NOLOGGING corruption once the database is recovered?
Check For Logging / Nologging On DB Object(s) (Doc ID 269274.1)
ORA-1578 / ORA-26040 Corrupt blocks by NOLOGGING - Error explanation and solution (Doc ID 794505.1)
REFERENCES
NOTE:1615996.1 - RMAN-06100 or RMAN-06102 during restore/duplicate
NOTE:1338193.1 - How to Move/Restore DB to New Host and File System using RMAN
NOTE:794505.1 - ORA-1578 / ORA-26040 Corrupt blocks by NOLOGGING - Error explanation and solution
NOTE:558408.1 - RMAN DUPLICATE / RESTORE a database to a higher patchset
NOTE:1481151.1 - RMAN "restore... Validate [header]" Lists Full Or L0 Backups Only
NOTE:369644.1 - Frequently Asked Questions about Restoring Or Duplicating Between Different Versions And Platforms
NOTE:269274.1 - Check For Logging / Nologging On DB Object(s)
NOTE:1489027.1 - RMAN Restore/Duplicate Performs Implicit Crosschecking and Cataloging
NOTE:1335910.1 - Monitoring Restore/Recovery Progress