This document provides an overview of Oracle Real Application Clusters (RAC) 12c Release 2 from Oracle. It discusses how RAC 12c Release 2 focuses on improved scalability, availability, and efficient management. New features like Flex Clusters, service-oriented buffer cache access, and pluggable database isolation are highlighted as providing better performance, availability, and scalability. Links to additional resources on Oracle RAC internals and scalability are also provided.

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Oracle
Real
Applica@on
Clusters
(RAC)
12c
Release
2
–
Overview
Markus
Michalewicz
Senior
Director
of
Product
Management,
Oracle
RAC
Development
December
6th,
2016
Markus.Michalewicz@oracle.com
@OracleRACpm
hPp://www.linkedin.com/in/markusmichalewicz
hPp://www.slideshare.net/MarkusMichalewicz

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3
Oracle
Database
12c
Rel.
2
Real
Applica@on
Clusters
(RAC)
It’s
all
about
scalability,
availability
and
efficient
management
BePer
availability
(due
to
reduced
reconfigura@on
@mes)
BePer
scalability
(for
singleton
services)
Efficient
management
for
large
scale
deployments

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4
Oracle
Database
12c
Rel.
2
Real
Applica@on
Clusters
(RAC)
It’s
all
about
scalability,
availability
and
efficient
management
BePer
availability
(due
to
reduced
reconfigura@on
@mes)
BePer
scalability
(for
singleton
services)
Efficient
management
for
large
scale
deployments

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5
Oracle
RAC
Scalability
–
A
Brief
Review
Oracle
RAC
scalability
• is
independent
of
the
number
of
nodes
• does
not
require
applica@on
changes
(unlike
sharding)
Oracle
RAC
scales
• most
of
the
enterprise
solu@ons
used
today
✔
Oracle
RAC
scales
• Oracle
Mul@tenant
Oracle
RAC
scales
• Oracle
Database
In-­‐Memory

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✔
hPp://www.slideshare.net/MarkusMichalewicz/
oracle-­‐rac-­‐internals-­‐the-­‐cache-­‐fusion-­‐edi@on
hPp://www.slideshare.net/MarkusMichalewicz/
paper-­‐oracle-­‐rac-­‐internals-­‐the-­‐cache-­‐fusion-­‐edi@on
hPp://www.slideshare.net/MarkusMichalewicz/
oracle-­‐rac-­‐customer-­‐proven-­‐scalalbility
6
www.slideshare.net/MarkusMichalewicz/oracle-­‐
mul@tenant-­‐meets-­‐oracle-­‐rac-­‐ioug-­‐2014-­‐version
hPp://www.slideshare.net/MarkusMichalewicz/
oracle-­‐database-­‐inmemory-­‐meets-­‐oracle-­‐rac
Oracle
RAC
Scalability
–
More
Informa@on
h"p://www.slideshare.net/MarkusMichalewicz

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Improved
scaling
for
all-­‐HUB,
Standalone
Clusters
7
Flex
Cluster-­‐based
Scaling
Oracle
RAC
12c
Release
2
–
Scaling
in
Two
Dimensions

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Improved
scaling
for
all-­‐HUB,
Standalone
Clusters
8
Flex
Cluster-­‐based
Scaling
Oracle
RAC
12c
Release
2
–
Scaling
in
Two
Dimensions

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Service-­‐oriented
Buffer
Cache
Access
determines
the
data
(on
database
object
level)
accessed
by
the
service
and
masters
this
data
on
the
node
on
which
the
(singleton)
service
is
offered,
which
improves
data
access
performance.
9
Pluggable
Database
and
Service
IsolaKon
improves
performance
by
reducing
DLM
opera@ons
for
PDBs
/
Services
not
offered
in
all
instances
and
op@mizing
block
opera@ons
based
on
in-­‐memory
block
separa@on.
Op@mized
Singleton
Workload
Scaling

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Improved
scaling
for
all-­‐HUB,
Standalone
Clusters
10
Flex
Cluster-­‐based
Scaling
Oracle
RAC
12c
Release
2
–
Scaling
in
Two
Dimensions

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Improved
scaling
for
all-­‐HUB,
Standalone
Clusters
11
Flex
Cluster-­‐based
Scaling
Oracle
RAC
12c
Release
2
–
Scaling
in
Two
Dimensions

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Introduced
during
OOW
2013:
hPp://www.slideshare.net/
MarkusMichalewicz/
understanding-­‐oracle-­‐rac-­‐12c-­‐
internals-­‐oow13-­‐con8806
12
Recommended
during
OOW
2014:
hPp://www.slideshare.net/
MarkusMichalewicz/oracle-­‐
rac-­‐12102-­‐opera@onal-­‐best-­‐prac@ces
The
standard
going
forward
(every
Oracle
12c
Rel.
2
cluster
is
a
Flex
Cluster
by
default.)
Oracle
Flex
Cluster
-­‐
A
Brief
Review

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13
Under
the
Hood:
Any
New
Install
Ends
Up
in
a
Flex
Cluster
[GRID]>
crsctl
get
cluster
name
CRS-­‐6724:
Current
cluster
name
is
'SolarCluster'
[GRID]>
crsctl
get
cluster
class
CRS-­‐41008:
Cluster
class
is
'Standalone
Cluster'
[GRID]>
crsctl
get
cluster
type
CRS-­‐6539:
The
cluster
type
is
'flex'.

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Use
Case
1:
Massive
Parallel
Query
RAC
Overlay
your
Hadoop
Cluster
(HDFS)
with
an
Oracle
Flex
Cluster
to
access
data
in
Hadoop
via
SQL
and
perform
cross-­‐data
(adhoc)
analysis
using
standard
interfaces.
14
Use
Case
2:
RAC
Reader
Nodes
Use
Read-­‐Only
workload
(WL)
on
read-­‐mostly
Leaf
node
instances
for
adoc
data
analysis
scaled
across
hundreds
of
nodes
with
no
delay
in
accessing
updated
data,
without
any
impact
on
OLTP
performance*
and
with
bePer
HA**
Oracle
Flex
Cluster
–
the
Scalable
Architecture
**
A
Leaf
node
failure
does
not
impact
any
other
node.
*
Read-­‐only
WL
on
Leaf-­‐instances
will
scale.

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Connect
Leaf
nodes
to
storage
Leaf
nodes
for
applica@ons
do
not
require
direct
storage
access;
running
database
instances
on
Leaf
nodes
does.
15
Install
Oracle
Database
Home
on
all
nodes
and
as
needed.
If
you
ever
want
to
run
a
database
instance
on
a
Leaf
node,
it
needs
a
database
home
as
any
other
node.
Extend
public
network
to
Leaf(s)
For
RAC
Reader
Nodes
use
case
only,
enable
a
public
network
connec@on
on
Mars
by
extending
the
network
and
listener
resources
to
the
leaf.
Run
a
Database
Instance
on
a
Leaf
Node
–
Prepara@on

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Create
a
Policy-­‐Managed
RAC
DB
RAC
Reader
Nodes
as
well
as
Massive
Parallel
Query
RAC
require
a
Policy-­‐
Managed
database.
Admin-­‐managed
DBs
cannot
be
extended
to
Leafs.
16
For
Massive
Parallel
Query
RAC,
create
new
server
pools
along
with
the
database.
Make
sure
to
create
a
“Parallel
Query
Server
Pool”.
For
RAC
Reader
Nodes,
Create
database
on
HUB
nodes
the
addi@on
of
database
instances
on
Leaf
nodes
is
dynamic
and
managed
via
command
line.
Run
a
Database
Instance
on
a
Leaf
Node
–
DB
Crea@on
Serverpool
OLTP
was
pre-­‐created
using
the
oracle
user.
Policy
management
allows
for
an
easy
re-­‐
assignment
of
a
Leaf
nodes
to
other
tasks.

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For
RAC
Reader
Nodes,
add
a
“Reader
Farm”
(RF)
pool
to
the
system
using
the
“add
service”
command
(dynamic).
17
Summary
Connect
Note
that
if
a
Leaf
node
is
used
for
Massive
Parallel
Query
RAC,
it
should
not
allow
for
direct
connec@ons
to
the
Leaf
node
instance.
Run
RAC
Reader
Nodes
–
Finaliza@on
(Re-­‐)star@ng
the
OLTPWL
Service
finalizes
the
DWHWL
service
setup.

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Oracle
Database
In-­‐Memory
–
ideal
for
RAC
Reader
Nodes
18
It’s
easy
to
run
Oracle
Database
In-­‐Memory
on
Leaf
Nodes:
alter system set
inmemory_size=100M
scope=spfile sid=‘*’;
Emphasizing
Leaf
Node
Usage
by
using
instance-­‐specific
senngs
is
“work
in
progress”
Run
Oracle
Database
In-­‐Memory
on
Leaf
Node
Instances
The
IMDB
Colum
Store
will
be
ac@vated
aoer
instance
restart.
A
min.
100MB
Column
Store
size
is
required.
Column
Stores
need
to
be
equally
sized
across
all
instances.
select
INST_ID,
pool,
alloc_bytes,
alloc_bytes,
used_bytes
from
GV$INMEMORY_AREA;

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19
Oracle
Database
12c
Rel.
2
Real
Applica@on
Clusters
(RAC)
It’s
all
about
scalability,
availability
and
efficient
management
BePer
availability
(due
to
reduced
reconfigura@on
@mes)
BePer
scalability
(for
singleton
services)
Efficient
management
for
large
scale
deployments

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Improved
availability
for
all-­‐HUB,
Standalone
Clusters
20
Flex
Cluster-­‐based
availability
–
here:
Node
WeighKng
Availability
due
to
Autonomous
Health
Framework
conKnuously
working
for
you
Oracle
RAC
12c
Rel.
2
Three
Dimensions
of
Availability

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Availability
due
to
Autonomous
Health
Framework
conKnuously
working
for
you
Flex
Cluster-­‐based
availability
–
here:
Node
WeighKng
Improved
availability
for
all-­‐HUB,
Standalone
Clusters
21
Oracle
RAC
12c
Rel.
2
Three
Dimensions
of
Availability

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Pluggable
Database
and
Service
IsolaKon
improves
availability
by
ensuring
that
instance
failures
of
instances
only
hos@ng
singleton
PDBs
will
not
impact
other
instances
of
the
same
RAC-­‐based
CDB.
22
Near
Zero
DownKme
Reconfig.
via
“Buddy
Instances”
which
track
modified
data
blocks
on
other
nodes
to
quickly
iden@fy
blocks
requiring
recovery,
which
allows
for
rapid
processing
of
new
transac@ons
in
case
recovery
is
needed.
Op@mized
(Singleton)
Reconfigura@on
Time
4x
faster

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Availability
due
to
Autonomous
Health
Framework
conKnuously
working
for
you
Improved
availability
for
all-­‐HUB,
Standalone
Clusters
23
Flex
Cluster-­‐based
availability
–
here:
Node
WeighKng
Oracle
RAC
12c
Rel.
2
Three
Dimensions
of
Availability

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24
• Pre-­‐12.2,
node
evic@on
follows
a
rather
“ignorant”
paPern
– Example
in
a
2-­‐node
cluster:
The
node
with
the
lowest
node
number
survives.
• Customers
must
not
base
their
applica@on
logic
on
which
node
survives
the
split
brain.
– As
this
may(!)
change
in
future
releases
Node
Evic@on
Basics
h"p://www.slideshare.net/MarkusMichalewicz/oracle-­‐clusterware-­‐node-­‐management-­‐and-­‐voKng-­‐disks
✔
1
2

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25
• Node
Weigh@ng
is
a
new
feature
that
considers
the
workload
hosted
in
the
cluster
during
fencing
• The
idea
is
to
let
the
majority
of
work
survive,
if
everything
else
is
equal
– Example:
In
a
2-­‐node
cluster,
the
node
hos@ng
the
majority
of
services
(at
fencing
@me)
is
meant
to
survive
Node
Weigh@ng
in
Oracle
RAC
12c
Release
2
Idea:
Everything
equal,
let
the
majority
of
work
survive
✔
1
2

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A
three
node
cluster
will
benefit
from
“Node
Weigh@ng”,
if
three
equally
sized
sub-­‐clusters
are
built
as
s
result
of
the
failure,
since
two
differently
sized
sub-­‐clusters
are
not
equal.
26
Secondary
failure
consideraKon
can
influence
which
node
survives.
Secondary
failure
considera@on
will
be
enhanced
successively.
A
fallback
scheme
is
applied
if
considera@ons
do
not
lead
to
an
ac@onable
outcome.
Let’s
Define
“Equal”
✔
Public
network
card
failure.
“Conflict”.

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CSS_CRITICAL
can
be
set
on
various
levels
/
components
to
mark
them
as
“cri@cal”
so
that
the
cluster
will
try
to
preserve
them
in
case
of
a
failure.
27
CSS_CRITICAL
will
be
honored
if
no
other
technical
reason
prohibits
survival
of
the
node
which
has
at
least
one
cri@cal
component
at
the
@me
of
failure.
A
fallback
scheme
is
applied
if
CSS_CRITICAL
senngs
do
not
lead
to
an
ac@onable
outcome.
CSS_CRITICAL
–
Fencing
with
Manual
Override
crsctl
set
server
css_criKcal
{YES|NO}
+
server
restart
srvctl
modify
database
-­‐help
|grep
cri@cal
…
-­‐css_cri@cal
{YES
|
NO}
Define
whether
the
database
or
service
is
CSS
cri@cal
✔
Node
evic@on
despite
WL;
WL
will
failover.
“Conflict”.

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• Leaf
nodes
require
at
least
one
Hub
node
in
the
cluster
to
which
they
can
connect.
• If
a
Hub
node
fails,
all
Leaf
nodes
connected
to
the
failed
Hub
node
re-­‐connect
to
another
Hub.
– Failover
is
transparent
…
• …
on
cluster
level.
• …
on
the
Leaf
nodes.
• …
for
instances
running
on
the
Leaf
nodes.
Last
but
Not
Least
–
Leaf
Node
Failover
EarthVenus
Oracle GI | HUB Oracle GI | HUB
Oracle RAC Oracle RAC
28
Mars
Oracle GI | Leaf
Oracle RAC

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29
Oracle
Database
12c
Rel.
2
Real
Applica@on
Clusters
(RAC)
It’s
all
about
scalability,
availability
and
efficient
management
BePer
availability
(due
to
reduced
reconfigura@on
@mes)
BePer
scalability
(for
singleton
services)
Efficient
management
for
large
scale
deployments

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gridSetup
and
zip-­‐based
install
allow
for
a
simple
unzip
to
install
the
Grid
Home
and
node
management
(addNode)
thereaoer
30
ASM
Management
for
NFS-­‐based
Clusterware
files
for
easier
management
and
thereby
bePer
availability.
Separate
Diskgroup
for
Grid
Infrastructure
Management
Repository
(GIMR)
allows
for
more
flexibility
during
Grid
Infrastructure
Installa@on
BePer
Management
Thanks
to
Your
Feedback
$ORACLE_HOME/gridSetup.sh
Using
these
and
other
technologies,
an
average
(2-­‐4
nodes)
cluster
can
be
installed
in
less
than
an
hour
with
proper
prepara@on.
Configure
ASM
on
NFS

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What
If…You
have
Hundreds
of
Environments
And
what
if…
– Sooware
Installa@on
– Storage
configura@on
– Diagnos@cs
setup
…
would
have
to
be
performed
only
once
and
can
then
be
re-­‐used
mulKple
Kmes?
…
allowing
you
to
save
many
hours
performing
these
@ring
tasks?
31

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Cluster
Domain
Simplifica@on
and
Efficiency
through
Centraliza@on
Facilita@ng
…
– Rapid
Home
Provisioning
(RHP)
– Automa@c
Storage
Management
(ASM)
– Autonomous
Health
Framework
(AHF)
…
hosted
on
a
dedicated
cluster
–
the
Domain
Services
Cluster
(DSC)
–
all
three
management
tasks
can
be
centralized
and
diagnos@cs
can
be
op@mized
for
Member
Clusters
in
the
Cluster
Domain.
32
Only
some
of
the
benefits
of
the
new
Cluster
Domain-­‐based
management
Domain
Services
Cluster
RHP
AHF

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33
Domain
Services
Cluster
Cluster
Domain
IO
Service
ASM
Service
Database
Member
Cluster
Uses
ASM
Service
Database
Member
Cluster
Uses
IO
&
ASM
Service
of
DSC
Trace
File
Analyzer
(TFA)
Service
Mgmt
Repository
(GIMR)
Service
ApplicaKon
Member
Cluster
GI
only
Database
Member
Cluster
Uses
local
ASM
Shared
ASM
AddiKonal
OpKonal
Services
Rapid
Home
Provisioning
(RHP)
Service
Private
Network
SAN
NAS
1 2 3 4

34. Copyright
©
2016,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Configure
an
Oracle
Domain
Services
Cluster
(DSC)
as
part
of
the
gridSetup-­‐based
install.
A
DSC
install
follows
the
“Standalone
Cluster”
install.
34
Create
a
credenKal
file
for
each
Member
Cluster
you
want
to
deploy
and
make
it
accessible
to
the
server
on
which
you
will
run
the
Member
Cluster
install.
Run
gridSetup
on
the
server
on
which
you
want
to
run
the
Member
Cluster
install
and
provide
access
to
the
credenKal
file
when
requested.
Then
“follow
the
instruc@ons
on
the
screen.”
How
to
Create
a
Cluster
Domain
The
Member
Cluster
will
use
only
services
for
which
it
has
creden@als.
Configure
an
Oracle
Domain
Services
Cluster

35. Copyright
©
2016,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Autonomous
Health
Framework
works
more
efficiently
for
you
on
the
DSC,
as
con@nuous
analysis
is
taken
off
the
produc@on
cluster.
35
The
DSC
is
the
ideal
hos@ng
environment
for
Rapid
Home
Provisioning
(RHP).
Oracle
ASM
12c
Rel.
2
based
storage
consolidaKon
is
best
performed
on
the
DSC,
as
it
enables
numerous
addi@onal
features
and
use
cases.
Proven
Features
–
Even
More
Beneficial
on
the
DSC

36. Copyright
©
2016,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Summary
• Oracle
RAC
12c
Rel.
2
provides
– BePer
Scalability
• Inherently
as
part
of
the
database
• Via
making
Flex
Cluster
the
standard
– BePer
Availability
• Inherently
as
part
of
the
database
• On
cluster-­‐level
via
Node
Weigh@ng
– Efficient
Management
for
large
scale
deployments
• Inherently
as
part
of
the
the
Installer
and
RHP
• Via
Cluster
Domain-­‐based
Management
36