Tuesday, August 26, 2008

RMAN-06172: no autobackup found

Error Description:
While performing disaster recovery I get the error RMAN-06172 as below.

RMAN> restore spfile to pfile '/oracle/app/oracle/product/10.2.0/db_1/dbs/initARJU.ora' from '/backup1/snap/june/ctl_sp_bak_c-448149146-20080607-00';

Starting restore at 27-AUG-08
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=36 devtype=DISK

RMAN-00571: ====================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ====================================================
RMAN-03002: failure of restore command at 08/27/2008 00:42:41
RMAN-06172: no autobackup found or specified handle is not a valid copy or piece

Cause of The Error
To perform restore operation to a new host you must have at least one autobackup of the controlfile. If you don't have autobackup of the controlfile then you would not be able to perform disaster recovery. For example if you have snapshot of controlfile backup then you will not be able to restore spfile or controlfile.

Solution of The Problem
1)To perform a disaster recovery, the minimum required set of backups is backups of some datafiles, some archived redo logs generated after the time of the backup, and at least one autobackup of the control file. So find autobackup of the controlfile and use it for restore operation.

Also ensure that you have autobackup intact and your autobackup is not corrupted. If you have corrupted backup then you will get above error.

My autobackup piece is /export/home/oracle/8rji9vrq_1_1 and so I used,
RMAN> restore spfile from '/export/home/oracle/8rji9vrq_1_1';

2)In situation you have autobackup of controlfile and it is not corrupted then still you can get the error. It is because of platform difference in endian format. It was because of BIG endian or LITTLE endian format. If you take backup in BIG endian platform and want to restore it to LITTLE endian format then above error will appear. You can check the endian format by below query.
SQL> set linesize 100
SQL> col PLATFORM_NAME format a80
SQL> select PLATFORM_NAME, ENDIAN_FORMAT from V$TRANSPORTABLE_PLATFORM;

PLATFORM_NAME                                                                    ENDIAN_FORMAT
-------------------------------------------------------------------------------- --------------
Solaris[tm] OE (32-bit)                                                          Big
Solaris[tm] OE (64-bit)                                                          Big
Microsoft Windows IA (32-bit)                                                    Little
Linux IA (32-bit)                                                                Little
AIX-Based Systems (64-bit)                                                       Big
HP-UX (64-bit)                                                                   Big
HP Tru64 UNIX                                                                    Little
HP-UX IA (64-bit)                                                                Big
Linux IA (64-bit)                                                                Little
HP Open VMS                                                                      Little
Microsoft Windows IA (64-bit)                                                    Little
IBM zSeries Based Linux                                                          Big
Linux 64-bit for AMD                                                             Little
Apple Mac OS                                                                     Big
Microsoft Windows 64-bit for AMD                                                 Little
Solaris Operating System (x86)                                                   Little
IBM Power Based Linux                                                            Big

17 rows selected.

We see Solaris[tm] OE (32-bit) or Solaris[tm] OE (32-bit) has big endian format but Solaris Operating System (x86) has little endian format. So we can't perform any restore operation in Microsoft Windows 64-bit for AMD or Solaris Operating System (x86) or Microsoft Windows IA (32-bit) (All these has Little endian format) from backup that was taken from Big endian format like Solaris[tm] OE (32-bit) or Solaris[tm] OE (32-bit) or IBM Power Based Linux or IBM zSeries Based Linux or HP-UX (64-bit) or AIX-Based Systems (64-bit).

If you try to restore in Little edian format, from backup taken in Big endian format platform RMAN can't read the backuppiece and will return,
RMAN-00571: ====================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ====================================================
RMAN-03002: failure of restore command at 08/27/2008 00:42:41
RMAN-06172: no autobackup found or specified handle is not a valid copy or piece

The solution is to use same endian format.

Related Documents
RMAN-06026, RMAN-06023 During Restore Using RMAN
ORA-19573: cannot obtain exclusive enqueue for datafile 1

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