RMAN an introduction
RMAN (Recovery Manager) recovery is based on SCN ( system change numbers) - they are an expression of linear date time expressions. They are also called technically the change vectors. which represents the time and transaction. The transaction means
1. internal (recursive call) transactions also building metadata.
2. application data transactions occupying the storage with the DML statements.
RMAN Backup Concepts
RMAN Backup Concepts (source Oracle)
Media Recovery enabled - RPO and RTO can be implemented.
Media Recovery disabled - RPO and RTO are irrelavent.
Backup can be taken using RMAN in those two states. Media Recovery Enabled (database in archivelog mode) and Media Recovery Disabled (database in noarchivelog mode).
BackingUpTheDatabase
Backing Up the Database (Source Oracle)
Use the BACKUP command to back up all or part of your database.
Backing Up the Database: Advanced Topics to learn about more advanced topics such as backup optimization, duplexing, backup encryption, and restartable backups
Oracle Data Guard Concepts and Administration to learn how to perform RMAN backup and recovery in a Data Guard environment
OracleFlashback
Oracle Database includes the following logical flashback features:
Oracle Database includes the following logical flashback features:
Oracle Flashback Query
You can specify a target time and run queries against a database, viewing results as they would appear at the target time. To recover from an unwanted change like an update to a table, you could choose a target time before the error and run a query to retrieve the contents of the lost rows. Oracle Database Development Guide explains how to use this feature.
Purpose of Backup and Recovery
1. Oracle Backup and Recovery Solutions
Purpose of Backup and Recovery:
As a backup administrator, your principal duty is to devise, implement, and manage a backup and recovery strategy. In general, the purpose of a backup and recovery strategy is to protect the database against data loss and reconstruct the database after data loss. Typically, backup administration tasks include the following:
RMAN Environment
RMAN Environment
Recovery Manager (RMAN) is an Oracle Database client that performs backup and recovery tasks on your databases and automates administration of your backup strategies. It greatly simplifies backing up, restoring, and recovering database files.
Rman at work
Connecting to RMAN with "NOCATALOG" and "CATALOG"
"rman" client application can be opened directly from command prompt
c:\Oracle\bin>set ORACLE_SID=srinivas
c:\Oracle\bin>echo %ORACLE_SID%
srinivas
c:\Oracle\bin>rman
RMAN Troubleshooting
Troubleshooting RMAN
Run the following command to find if RMAN sessions exist in the database instance (format the output for readability):
SELECT p.SPID,
s.EVENT,
s.SECONDS_IN_WAIT AS SEC_WAIT,
sw.STATE,
s.CLIENT_INFO
FROM V$SESSION_WAIT sw,
V$SESSION s,
V$PROCESS p
WHERE sw.EVENT LIKE '%Backup%'
AND s.SID=sw.SID
AND s.PADDR=p.ADDR;
Oracle SW installation
Installing the Oracle Database Software on the Destination Host
When the source and destination host are different, you must install the Oracle Database software on the destination host, so that the auxiliary instance can be created.
Note:
Ensure that you install the same release of Oracle Database software, with the same patch level, on both the source and destination host.
Duplicating database prerequisites
Naming Duplicate Database Files
When you duplicate a database, RMAN generates names for the database files in the duplicate database. This includes the control files, data files, temp files, and online redo log files.
Depending on your duplication scenario, you can name the duplicate database files by using one of the following techniques:
a. Using the Same Names for Database Files in the Source Database and Duplicate Database
b. Using Different Names for the Database Files in the Source Database and Duplicate Database