RMAN incremental backups fails even though full backup exists

Originally posted here,

http://hemantoracledba.blogspot.in/2013/02/backup-and-recovery-with-intermediate.html

Asked why the incremental backup fails

oracle@linux64 ~]$ rman target /

Recovery Manager: Release 11.2.0.1.0 - Production on Thu Feb 7 21:30:18 2013

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

connected to target database: ORCL (DBID=1229390655)

RMAN> backup database plus archivelog;

Starting backup at 07-FEB-13
current log archived
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=196 device type=DISK
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence

After some transactions and a database kept in archive log mode,

RMAN> backup incremental level 1 cumulative database;

Starting backup at 07-FEB-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=67 device type=DISK
no parent backup or copy of datafile 2 found
no parent backup or copy of datafile 1 found
no parent backup or copy of datafile 3 found
no parent backup or copy of datafile 4 found
no parent backup or copy of datafile 5 found
channel ORA_DISK_1: starting incremental level 0 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set

Observed? no parent backup copy found? even though you have full backup exists.

The reason, if you look at the first backup command that was backup database a full backup not the level 0 , if you want to take a level, you will need to use backup level 0 database.

The answer to the hemant’s post is,

A level 0 incremental backup is physically identical to a full backup. The only difference is that the level 0 backup is recorded as an incremental backup in the RMAN repository, so it can be used as the parent for a level 1 backup.

As you have used backup database plus archivelog instead of backup incremental level 0 database. Thats why rman is unable to find the parent backup

Hemant’s Answer

All : See the update on 08-Feb.

Oracle does not treat a BACKUP [FULL] DATABASE as a base from which it can take L1 Backups.

-Thanks

Geek DBA