Implementing and Assessing Oracle RMAN Backup: Proficient at RMAN Commands and Recovery Process
This step-by-step guide will walk you through the steps necessary to validate and assess your Oracle database backups. We’ll delve into areas including the significance, the objectives, and the tactics involved in testing database backups.
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We will be employing the Oracle database as our illustrative example throughout this tutorial.
Case Study: Verifying Oracle RMAN Database Backups:
Assessing Oracle Database Backup using RMAN
We’ve broken it down into the next four segments:
- Concept of backup?
- Need for backups?
- Methodology of backup?
- Verifying your database backup strategy – Recovery tactics?
Recommended Reading => Everything about Database testing
What Does a Database Backup Mean?
Before delving into the specifics of backups, it’s essential to appreciate the organization’s most valuable resource – Data. In the context of an Oracle database, the term “database” is characterized in the Oracle Database Testing series here.
Data forms the bedrock of any organization. Industries like retail or banking consistently house extensive data, including end-user and system data. Database supervisors and system administrators in charge of safeguarding this data must grasp its gravity and ensure constant access through regular backups.
A backup is a precise duplicate of your database that can act as a restoration medium in case of data loss.
What’s the Purpose of Database Backups?
Imagine a banking institution holding information on millions of clients, including account details, names, beneficiaries, and account balances. The fallout from losing this data would be devastating. The same goes for a telecom company with vital customer details like phone numbers, addresses, and payment facts. Losing this information would implicate grave fiscal and operational repercussions.
Organizations can safeguard themselves from such instances by backing up data. In case of disk malfunction or other storage problems, a backup offers a way to recover the data and avert the loss of important information.
Moreover, backups offer an insurance policy against human errors. If data is unexpectedly altered or lost, backups can be used to restore the tainted data.
How Can We Backup the Database?
Numerous strategies are available for backing up an Oracle Database, such as physical and logical backups.
Technique #1) Physical Backups::
- Resort to third-party backup solutions such as Veritas NetBackup, SAP, IBM Tivoli Manager, EMC, or HP.
- Perform user-managed backups with the help of operating system utilities like copy (Windows) or cp (Unix).
- Use Oracle Secure Backup.
- Adopt Oracle Recovery Manager (RMAN) – this is the suggested tactic.
Method #2) Logical Backups:
- Select from conventional export/import utilities or Datapump utilities. Logical backups pivot around exporting logical data like tables and indexes, independent of the concrete location of these artefacts.
Being aware of the physical and logical storage structures of a database is paramount to devising a sound backup scheme.
While each mechanism has its pros and cons, the importance of physical backups cannot be overstated. Relying solely on logical backups does not offer adequate protection against physical data corruption or hardware faults in your storage. A comprehensive backup and recovery strategy must incorporate physical backups.
While implementing any of these strategies, it’s advisable to test backup and recovery formulas on a duplicate test system. This allows anticipating the recovery time in unforeseen circumstances.
This discussion mainly dwells on RMAN backups, spotlighting the backup process.
Backup Commands for Oracle RMAN (Oracle Recovery Manager)
You can perform data backups using the Enterprise Manager (GUI) mode or via the OS command line prompt.
RMAN is a powerful and refined tool offered by Oracle for backup and recovery functions.
RMAN comes pre-installed with the Oracle database installation, eliminating the need for additional installations.
The RMAN environment comprises two distinct parts:
1) The target database (the database to backup and recover)
2) The RMAN client, which interprets user requests and accomplishes them on the user’s behalf while connecting to the target database.
To establish a connection to the database using RMAN, use the command shown:
C:Usersxyz> rman target / Recovery Manager: Release 188.8.131.52.0 - Production on Sun Sep 28 17:32:48 2014 Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved. connected to target database: ORCL (DBID=1361070653) RMAN>
The DBID signifies the unique identifier for the database you are accessing. In this instance, the database is named ORCL.
In this instance, we will backup the data from the ORCL database. We need to define a location or directory to store the backup.
We can use a unique directory named db_recovery_file_dest as the backup location. We can also define the size of this parameter with db_recovery_file_dest_size, which sets the size for the backup location. It is recommended to allocate adequate space based on the actual data size in the database, keeping in mind archive logs (offline redo logs recording changes to data blocks).
A sound backup strategy usually comprises all files related to the database, such as datafiles, control files, parameter files, network-related files, and archived redo log files. RMAN or other physical backup tools cater to datafiles, control files, parameter files, and archived redo log files, while network-related files must be backed up manually employing OS utilities like cp or copy.
To initiate the backup of the database, execute the following command:
“Backup database” – it’s as straightforward as it sounds. Let’s move forward to backup our ORCL database.
RMAN> backup database;
Here, we have already connected to the target database (ORCL) and executed the “backup database” command.
RMAN> backup database; Starting backup at 05-OCT-14 using target database control file instead of recovery catalog allocated channel: ORA_DISK_1 channel ORA_DISK_1: SID=198 device type=DISK channel ORA_DISK_1: starting full datafile backup set channel ORA_DISK_1: specifying datafile(s) in backup set input datafile file number=00001 name=D:APP1SUNTYADAORADATAORCLSYSTEM01.DBF input datafile file number=00002 name=D:APP1SUNTYADAORADATAORCLSYSAUX01.DBF input datafile file number=00005 name=D:APP1SUNTYADAORADATAORCLEXAMPLE01.DBF input datafile file number=00003 name=D:APP1SUNTYADAORADATAORCLUNDOTBS01.DBF input datafile file number=00004 name=D:APP1SUNTYADAORADATAORCLUSERS01.DBF channel ORA_DISK_1: starting piece 1 at 05-OCT-14 channel ORA_DISK_1: finished piece 1 at 05-OCT-14 piece handle=D:APP1SUNTYADAFLASH_RECOVERY_AREAORCLBACKUPSET2014_10_05O1_MF_NNNDF_TAG20141005T162412_B328TXQG_.BKP tag=TAG20141005T162412 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:04:27 channel ORA_DISK_1: starting full datafile backup set channel ORA_DISK_1: specifying datafile(s) in backup set including current control file in backup set including current SPFILE in backup set channel ORA_DISK_1: starting piece 1 at 05-OCT-14 channel ORA_DISK_1: finished piece 1 at 05-OCT-14 piece handle=D:APP1SUNTYADAFLASH_RECOVERY_AREAORCLBACKUPSET2014_10_05O1_MF_NCSNF_TAG20141005T162412_B3293806_.BKP tag=TAG20141005T162412 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:00:04 Finished backup at 05-OCT-14
In this illustration,