Backup & recovery with rman
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Transcript of Backup & recovery with rman
Oracle DatabaseBackup & Recovery with RMAN
Internet & Network Security
Abid Hussain
Syed Muhammad Mohsin
Agenda
Types of failures and backups in Oracle
RMAN Architecture Manual vs. RMAN backups RMAN backup strategies Exemplary recovery scanarios
Types of failures
Instance Failure Usually connected with an Oracle process failure
Media Failure Disk failure, storage array controller failure etc.
Block Corruption Usually caused by bugs in Oracle software
Human error In most cases accidentally deleted/updated data
Database user or DBA
Disaster Fire, flood, earthquake, plane crash etc.
Backup options in Oracle
Physical backups Cold (off-line) backups
Full database only
Require downtime
Do not provide flexibility for point in time recovery (PiTR)
Hot (on-line) backups Different types of backups: full, incr. (cumulative, differential),
archivelogs
Different scopes: full database, tablespace(s) or datafile(s)
Do not require database downtime
Can be used to recover full database, single/multiple tablespace(s)/datafile(s) or a corrupted block
Database can be recovered to any point in time within assumed backup retention period
Backup options in Oracle (2)
Logical backups Logical copy of data in the database Support for different backup granularity Can be taken either with legacy Export/Import tools or
with Data Pump (10g)
Standby systems (Data Guard) Physical and logical standby databases
How hot backups are possible?
SGAServer p
roc.
DBWR LGWR
RedoLog
RedoLog
Db file
Db file
Db fileDb file
Lo
g a
rchiver
Archived redo logs
Backu
p p
roc.
Tapes
or
disks
system
RMAN architecture
TargetDatabase
RMAN Client
TargetDatabase
TargetDatabase
AuxiliaryDatabase
RMANCatalogSchema
Catalog Database
Types of RMAN hot backups Copy or backupset Full database backup Incremental backups (in 10g 2 levels available: 0 and 1)
Cumulative, differential Can be used to update a copy of the database
Archivelog backups Tablespace(s), datafile(s) backups
Differential incremental Cumulative incremental
Manual vs. RMAN backups
RMAN advantages: Supports incremental backup strategies
RMAN on-line backups are not so heavy for the system as manual on-line backups
RMAN can detect corrupted blocks
RMAN automatically track database structure changes
Provides easy, automated backup, restore and recovery operations
Keeps invenotory of taken backups
Can seamlessly work with third party media managers
Disadvantage: something new to learn RMAN concepts and command syntax sometimes are not intuitive
RMAN backup strategies RMAN allows many types of backups It possible to build own backup strategy that
suits given database best There are also Oracle recommended backup
strategies: Incremental backup strategy: level 0 backups + level
1 backups (cumulative and/or differential) and archivelog backups inbetween.
Incrementally updated database copy: 1 backup as copy of the whole database + incremental backups used to update the copy + archived redo logs.
• Automatic failover– Database down– Designated health-check
conditions– Or at request of an
application
• Failed primary automatically reinstated as standby database
• All other standby’s automatically synchronize with the new primary
PrimaryDatabase
Observer
PrimaryDatabasePrimary
DatabaseStandby
Database
Data Guard Fast-Start Failover
Role specific database services start automatically
2
StandbyDatabase
Database Tier- OracleReal Application Clusters
Application Tier - Oracle Application Server Clusters
Database Services
PrimaryDatabase
Primary Database
Standbybecomes primary database
Data GuardAutomaticFailover
1
FAN breaks clients out of TCP timeout.TAF/FCF automatically
reconnects applications to new primary
3
Standby Database
Data Guard Automatic Failover
Real-time Queries
ProductionDatabase
Continuous redo shipping, validation & apply
Real-time Reporting
Fast Incremental
Backups
•Offload read-only queries to an up-to-date physical standby
Real-time Reporting
Active Standby Database
Read-writeWorkload
Active Data Guard
•Use fast incremental backups on a physical standby – up to 20x faster
Primary Site Remote SiteDisaster Recovery
StandbyDatabase
Remote Standby
Database
ASYNC
Data Guard
PrimaryDatabase
SYNC
Ultimate High Availability
Primary Site Remote SiteDisaster Recovery
ASYNCData Guard
PrimaryDatabase
Remote Standby
Database
Ultimate High Availability