Validate command-RMAN for backup and recovery Verification

Validate command-RMAN for backup and recovery Verification

As an Oracle backup and recovery tool, RMAN provides us with powerful functions, including physical and logical detection of data files and validity detection of backup files.

First, let's take a look at RMAN's detection of data files. We know that when RMAN backs up data, it reads the data into the read cache, and then writes the data from the read cache to the write cache and finally writes the data to the database. During the process from read cache to write cache, RMAN performs physical consistency detection (db_block_checksum is not true) and logical consistency detection (the check logical option is used ). For example:

SQL> show parameter db_block

NAME TYPE VALUE
-----------------------------------------------------------------------------
Db_block_buffers integer 0
Db_block_checking string FALSE
Db_block_checksum string TRUE
Db_block_size integer 8192
SQL>

RMAN> backup tablespace test1;

Starting backup at 15:12:49
Using channel ORA_DISK_1
Channel ORA_DISK_1: starting full datafile backupset
Channel ORA_DISK_1: specifying datafile (s) in backupset
Input datafile fno = 00005 name =/home/app/oraten/oradata/oraten/test01.dbf
Channel ORA_DISK_1: starting piece 1 at 2014-11-06 15:12:50
RMAN-00571: ========================================================== ==============================
RMAN-00569: ==================== error message stack follows ==========================
RMAN-00571: ========================================================== ==============================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 11/06/2014 15:12:51
ORA-19566: exceeded limit of 0 blocks upt blocks for file/home/app/oraten/oradata/oraten/test01.dbf

Sometimes, we just want to verify whether the data file can be backed up, rather than the real backup, we can use the validate Command, as shown in

RMAN> backup validate database;

Starting backup at 15:14:23
Using channel ORA_DISK_1
Channel ORA_DISK_1: starting full datafile backupset
Channel ORA_DISK_1: specifying datafile (s) in backupset
Input datafile fno = 00001 name =/home/app/oraten/oradata/oraten/system01.dbf
Input datafile fno = 00003 name =/home/app/oraten/oradata/oraten/sysaux01.dbf
Input datafile fno = 00002 name =/home/app/oraten/oradata/oraten/undotbs01.dbf
Input datafile fno = 00005 name =/home/app/oraten/oradata/oraten/test01.dbf
Input datafile fno = 00004 name =/home/app/oraten/oradata/oraten/users01.dbf
Channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Channel ORA_DISK_1: starting full datafile backupset
Channel ORA_DISK_1: specifying datafile (s) in backupset
Including current control file in backupset
Including current SPFILE in backupset
Channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 15:14:27

Note: The physical damage block of test01.dbf is not found here. In my opinion, rman only reads the data file into the read cache and does not perform the following operations, that is to say, physical block detection has limited functions, but we can use it to detect the readability and location of physical files.

-------------------------------------- Recommended reading --------------------------------------

RMAN: Configure an archive log deletion policy

Basic Oracle tutorial-copying a database through RMAN

Reference for RMAN backup policy formulation

RMAN backup learning notes

Oracle Database Backup encryption RMAN Encryption

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