RMAN best practices for RAC

RMAN best practices for

Real Application Clusters (RAC)

Presented by : Syed Jaffer Hussain Slide # 1

Know your presenter

Syed Jaffer HussainDatabase Support Manager

20 years IT experience11+ years as an Oracle DBA

Oracle ACE DirectorOracle 10g Certified Master(OCM)

Oracle 10g RAC Certified ExpertOracle Certified Professional(OCP) v8i,9i,10g & 11g

ITIL v3 Foundation CertifiedAuthored Oracle 11g R1/R2 Real Application Clusters

EssentialsTwitter: @sjaffarhussain

http://jaffardba.blogspot.com


Managing backup and recovery operations in RMAN for RAC and non-RAC databases

are nearly identical ….


What will be covered

• RAC Vs RMAN – why and when.• RMAN overview.• Multi-channel configuration • Parallel recovery in RAC database.• Instance Vs Crash recovery in RAC.• Fast Recovery Area (FRA) for RAC database.• Snapshot Controlfile backup for RAC db in 11gR2.• Manage backup & recovery with Oracle Grid Control /EM.


RAC Vs RMAN – why and when

Real Application Clusters (RAC)

• High Availability(HA)• Failover.

• Scalability• Load balancing.

• It doesn’t safeguard your data from hardware failures or from any disasters.


Recovery Manager (RMAN)

• A command-line and EM tool.

• Best used for all sort of database backup & recovery operations.

• It doesn’t provide high availability


• RAC Vs RMAN – why and when.• RMAN overview.• Multi-channel configuration. • Parallel recovery in RAC database.• Instance Vs Crash recovery in RAC.• Fast Recovery Area (FRA) for RAC database.• Snapshot Controlfile backup for RAC db in 11gR2.• Manage backup & recovery using Enterprise Manager(EM).


RMAN overviewRecovery Manager

• Was first commercially introduced with Oracle v8.• A command-line and EM based tool.• Comes for absolutely free of cost, installed and

configured by default.• Intended for:

o Online/Offline backup and restore procedures.o Can back up Database, Tablespace, Datafile, and

Archived logs.• Supports incremental, fast incremental,

compressed & encrypted backups.• Detects [ALSO can repair ] data block corruptions.• Must required to backup datafiles configured on

Automatic Storage Management (ASM).• Can validate (test) backup without actually restoring.


Courtesy from Oracle docs.


• RAC Vs RMAN – why and when.• RMAN overview.• Configure multiple channels. • Parallel recovery in RAC database.• Instance Vs Crash recovery in RAC.• Fast Recovery Area (FRA) for RAC database.• Snapshot Controlfile backup for RAC db in 11gR2.• Manage backup & recovery with Oracle Grid Control /EM.


Configure multiple channelsMultiple channel configuration for RAC db instances

• Scale up the back up load on to multiple instances of RAC database by configuring multiple channels.


RMAN>

Channel 1

Channel 2

RACDB

RACDB1

RACDB2

Configure multiple channelsWorking examples

One time configuration in RMAN

RMAN> CONFIGURE DEVICE TYPE disk/tape PARALLELISM 2;RMAN> CONFIGURE CHANNEL ch1 CONNECT ‘sys/password@tns_inst1’;RMAN> CONFIGURE CHANNEL ch2 CONNECT ‘sys/password@tns_inst2’;

One time configuration with service name

RMAN> CONFIGURE DEVICE TYPE disk/tape PARALLELISM 2;RMAN> CONFIGURE CHANNEL ch1 CONNECT ‘sys/password@service_name’;

Run time configuration

RUN {ALLOCATE CHANNEL ch1 CONNECT ‘sys/password@tns_inst1’;ALLOCATE CHANNEL ch2 CONNECT ‘sys/password@tns_inst2’;

backup database …;RELEASE CHANNEL ch1;RELEASE CHANNEL ch2;}


Ensue LOAD_BALANCEturned onno TOTAF (failover)




Parallel recovery in RAC

Apply parallelism to faster restore/recovery operations

• Parallelism can be applied for instance, crash and media recovery operations to faster the process.

• During instance/crash recovery, Oracle database automatically applies the optimumdegree of parallelism.

• Based on the CPU count, Oracle sets an optimum number of parallelism while applying archive logs.

• Setting RECOVERY_PARALLELISM initialization parameter value to 0 or 1 disables instance/crash parallelism.





Instance Vs Crash recovery in RAC


o When an instance goes down abruptly for a various reasons, the subsequent instance startup requires the instance recovery.

o No manual intervention is required for instance/crash recovery. Oracle (SMON background process) automatically manages the process by applying online redo information.

o The mechanism of an instance recovery is to ensure the database consistency post instance failure.



Instance recovery = one or more [not ALL] instance(s) failure of a RAC database.

Crash recovery = failure of ALL instances of a RAC database.



Instance or Crash recovery done in TWO phases for a RAC database.

- Global Enqueue Service (LMS) background process

- System Monitor (SMON) background process



Instance 1

SMON PMON LGWR CKPT ARCn

Redo LogsArchive logs

Instance 2



RAC DB

Instance recovery of RAC database



Instance 1



Instance B



RAC DB


down



Instance 1



Instance B



RAC DB


up



Instance 1

PMON LGWR CKPT ARCn


Instance B



RAC DB


up

LMS

SMON

GRD recovery



Instance A



Instance B



RAC DB


LMS GRD recovery



Instance A



Instance B



RAC DB


GRD recovery

LMS



RAC DB

Crash recovery in a RAC database

Instance 1 Instance 2 Instance 2

Failure of all instances>>



RAC DB





RAC DB



The instance that comes up first performs the instance recovery for all instances of a RAC database




Fast Recovery Area(FRA) for RAC


Instance 1



Instance 2



RAC DB

Location destination Location destination

Flash Recovery Area(FRA) for RAC


Instance 1



Instance 2



RAC DB

Read permission

Location destination Location destination

Flash Recovery Area(FRA) for RAC


Instance 1

1

Redo Logs Archive logs

Instance 2

1 21 2

RAC DB

Fast Recovery Area (FRA)

FRA =ASMCFSShared Location (NFS)

Identified by the thread number

1 22




Snapshot Controlfile backup in 11gR2

• Must reside on a shared device in 11gR2 or later.

• All instances must have access to the snapshot controlfile.

• Same snapshot controlfile will be shared by all nodes of RAC db.

RMAN> CONFIGURE SNAPSHOT CONTROLFILE NAME TO <shared_location>;This must be done on EACH instance.

ORA-00245: control file backup operation failed





Manage B&R using Enterprise Manager


Manage B&R using Enterprise Manager


A big thank you to all

for

listening ...


You can write me at [email protected]

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