Oracle Recovery Manager (RMAN) 10g : Reloaded

Boris Gurov

Support Engineer

Oracle Bulgaria

Agenda

What is Recovery Manager? Automatic disk based recovery Optimized incremental backups Incrementally updated backups Just say no to shrinking backup windows A new twist to transportable tablespaces Q&A

Recovery Manager: Oracle’s Backup & Recovery Utility

Over 25 Man Years of Engineering Technology provides:

– Intimate knowledge of database file formats and recovery procedures

– Manages and automates the backup, restore, and recovery process

– Creates and maintains backup policies

– Catalogs all backup and recovery activities

– Operates on-line and in parallel for fast processing

– Corrupt block detection during backup and restore and the ability to validate backups

– Integrated with Enterprise Manager & 3rd party network backup products

Media Management Layer

Enterprise ManagerEnterprise Manager& 3& 3rdrd Party Tools Party Tools

Network

RecoveryRecoveryManagerManager

New World: Disk Based Data Recovery

Disk economics are close to tape

Disk is better than tape– Random access to any data

We rearchitected our recovery strategy to take advantage of these economics

– Random access allows us to backup and recover just the changes to the database

Backup and Recovery goes from hours to minutes

2000’s - 200 GB

1980’s - 200 MB

1000x increase

Flash Recovery Area Unified storage location for all recovery files and recovery related activities

in an Oracle Database.– Centralized location for control files, online redo logs, archive logs,

flashback logs, backups– A flash recovery area can be defined as a directory, file system, or ASM

disk group – A single recovery area can be shared by more than one database

Minimize the number of initialization parameters to set when you create a database

– Define a database area and flash recovery area location– Oracle creates and manages all files using OMF

Database Area Flash Recovery Area

Flash Recovery Area Space Management

Disk limit is reached and a new file needs to be written

into the Flash Recovery Area

Backup Files

to be deleted

Archive Logs &Database File

Backups

Warning Issued to user

Space Pressure occurs

RMAN updates

list of files that

may be deleted

12

Oracle

delete files that

are no longer

required on

disk.

Flash Recovery

Area

Benefits to Using a Flash Recovery Area

Unifies the storage location of related recovery files

Manages the disk space allocated for recovery files automatically

Simplifies database administrator tasks Much faster backup Much faster restore Much more reliable due to inherent reliability of disks

Change Tracking File Optimizes incremental

backups– Track which blocks have

changed since last backup

Integrated change tracking file– Changed blocks are

tracked as redo is generated

– RMAN backup automatically uses changed block list

101100101011000011101001011010101110011

ChangeTracking File

Flash RecoveryArea

The Size of the Change Tracking File

• Approximately 1/250000 of the total size of the database

• Depends on the number of the threads in RAC environment

• Depends on the number of the old backups (max 8 backups are tracked)

Enabling Block Change Tracking

– ALTER DATABASE ENABLE BLOCK CHANGE TRACKING

[USING FILE

‘/oracle/u101/changetrack/o1_mf_yzczmrr7_.chg‘];

– The Change Tracking Writer (CTWR) process– v$block_change_tracking view

STATUS

FILE

BYTES

Incremental Backup and Changed Tracking File

Benefits Faster

– Optimizes incremental backups to only backup those changed blocks directly

– Integrated with DB recovery and logging Better

– Uses less space since changes are tracked per block group

– RAC enabled Simpler

– Automatically integrates with backup and recovery – zero effort 

Incrementally Updated Backups

Eliminates the need to perform a whole database backup. Reduces the time required for media recovery since the image

copy is updated with the latest block changes.

RMAN

RECOVER COPY OF DATAFILE

RMANincremental

backup

Initiate Merge

IncrementallyUpdated Backups

Eliminate Shrinking Backup Window Syndrome!

Fully automatic disk based backup and recovery

– Set it and Forget it

Nightly incremental backup rolls forward recovery area backup

– Changed blocks are tracked in production DB

Full scan is never needed– Dramatically faster (20x)– Blocks validated to prevent

corruption of backup copy

Use low cost disk array for recovery area

Two Independent Disk Systems

Flash RecoveryArea

Nightly ApplyValidatedIncremental

WeeklyArchiveTo Tape

DatabaseArea

Oracle Suggested Strategy

Easy & Reliable– Integrates the

Oracle DB 10g features

Fast Recovery Options

– Backup and Recovery goes from hours to minutes

Automated Disk Based Backup & Recovery Benefits

Much faster backup– Just propagate changes to recovery area– Dramatic difference for large databases

Much faster restore – Copy backup files from the Flash Recovery Area– Or simply use the copy in the Flash Recovery

Area Much more reliable due to inherent reliability of disks

– Tapes not needed for normal backup/recovery, only for archiving

Backup Management

List RMAN backups– View files included

in a backup set Perform maintenance

– Remove obsolete backups with a single click

What is Transportable Tablespace?

OS copyFile 1 File

2expdat.dmp

File 1 File

2expdat.dmp

2424

Mechanism to quickly move a tablespace across Oracle databases

Most efficient means to move bulk data between databases.

– File is simply copied at OS level

Oracle10g Cross Platform Transportable Tablespace

Solaris (SPARC)

Open VMS (Intel IA64)

Windows (Intel IA32/64)

Linux (Intel IA32/64)

AIX (PowerPC)

HP-UX (PA-RISC)

Tru64 UNIX (Alpha)

HP-UX (Intel IA64)

Small Endian Platforms Big Endian Platforms

Simple File Copy Within These

Simple File Copy Within These

High SpeedFile Convert

RMAN

Cross Platform Transportable Tablespace Benefits

Fast data distribution in Data Warehousing environment (data marts)

Used for publishing structured data (i.e. catalogs on CDs)

Sharing of read only tablespaces by heterogeneous systems

Allowing a database to be migrated from one platform to another

Creating Compressed Backups

Compression of archive logs and backupses using LZ based approach

The compressed backupset is not be usable with pre– Oracle Database 10g

RMAN> BACKUP COMPRESSED BACKUPSET DATABASE;

RMAN> CONFIGURE DEVICE TYPE DISK PARALLELISM 2

BACKUP TYPE TO COMPRESSED BACKUPSET;

Other Oracle10g Backup & Recovery Enhancements Restore tolerates missing or corrupt backup

– Automatically fails over to previous backup

Automated recovery through a previous point in time recovery

– Recovery through resetlogs

Fully automated tablespace point-in-time recovery Automatic channel failover on backup or restore Time window based throttling of backups Tablespace Rename Drop Database

Resources

HA OTN: http://otn.oracle.com/deploy/availability

RMAN Discussion Forum http:// otn.oracle.com

MetaLink http:// MetaLink.oracle.com &Q U E S T I O N SQ U E S T I O N S

A N S W E R SA N S W E R S