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 Hussain
Database Support Manager
20 years IT experience
11+ years as an Oracle DBA
Oracle ACE Director
Oracle 10g Certified Master(OCM)
Oracle 10g RAC Certified Expert
Oracle Certified Professional(OCP) v8i,9i,10g & 11g
ITIL v3 Foundation Certified
Authored Oracle 11g R1/R2 Real Application Clusters
Essentials
Twitter: @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) Recovery Manager (RMAN)

• High Availability(HA) • A command-line and EM tool.
• Failover.
• Best used for all sort of database
• Scalability backup & recovery operations.
• Load balancing.

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



• RMAN overview.
• Multi-channel configuration.
• Manage backup & recovery using Enterprise Manager(EM).


RMAN overview
Recovery 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. Courtesy from Oracle docs.
• Must required to backup datafiles configured on
Automatic Storage Management (ASM).
• Can validate (test) backup without actually restoring.



• RMAN overview.
• Configure multiple channels.


Configure multiple channels
Multiple channel configuration for RAC db instances

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

RACDB1

Channel 1

RMAN> RACDB

Channel 2

RACDB2


Configure multiple channels
Working 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’; Ensue
LOAD_BALANCE
turned on
no TO
Run time configuration TAF (failover)

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;
}



• RMAN overview.


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 optimum
degree 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.



• RMAN overview.


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 recovery of RAC database

Instance 1 Instance 2

SMON PMON LGWR CKPT ARCn SMON PMON LGWR CKPT ARCn

Redo Logs Redo Logs
Archive logs Archive logs

RAC DB



Instance 1 Instance B
down


Redo Logs Redo Logs

RAC DB



Instance 1 Instance B

up


Redo Logs Redo Logs

RAC DB



LMS GRD Instance 1 Instance B
recovery

up


Redo Logs Redo Logs

RAC DB



LMS GRD Instance A Instance B
recovery


Redo Logs Redo Logs

RAC DB


Crash recovery in a RAC database

Failure of all instances>>

Instance 1

RAC DB



Instance 1

RAC DB



Instance 1

RAC DB

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



• RMAN overview.


Fast Recovery Area(FRA) for RAC



Redo Logs Redo Logs

Location destination Location destination
RAC DB


Flash Recovery Area(FRA) for RAC



Read permission

Redo Logs Redo Logs

Location destination Location destination

RAC DB


Flash Recovery Area(FRA) for RAC


Fast Recovery Area (FRA)

1 2 1 2 Identified by the thread number

2 1 2
1
Redo Logs Archive logs

FRA =
ASM
CFS
Shared Location (NFS)

RAC DB



• RMAN overview.


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



• RMAN overview.


Manage B&R using Enterprise Manager


A big thank you to all
for
listening ...
You can write me at sjaffarhussain@gmail.com


RMAN best practices for RAC

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