+

there’s just ONE problem

everyone has a right to

SIMPLICITY

SQL Server 2012Availability Groups

SQL Server 2012Availability Groups

complex

I can’t blame them

I felt the same way

I have to be intimidated

I have to be intimidated

I actually know afew things

the complex

is to start with what we

already know

the SECRET to understanding

SQL Server 2012Availability Groups

is NOT a new technology

SQL Server 2012Availability Groups

Failover Clustering

Database Mirroring+

database mirroringhow it works

MirrorPrincipal

WitnessApplication

SQL Server SQL Server

2

2

4

51

3>2 >3

Mirror is always redoing – it remains current

Commit

log data log data

database mirroringhow it works

*database snapshot

SYNCHRONOUS

MirrorPrincipal

Application

SQL Server SQL Server

2

2

4

51

3>2 >3

Mirror is always redoing – it remains current

Commit

log data log data

database mirroringhow it works

*database snapshot

ASYNCHRONOUS

DATABASE MIRRORING

can either be an HA or DR solution

*DATABASE protection

DATABASE MIRRORING

involves sending streams of active

transaction log records to and applying

them on the mirror server

DATABASE MIRRORING

operates on the physical layer (transaction log)

DATABASE MIRRORING

operating modes

high safety (synchronous)

DATABASE MIRRORING

operating modes

high performance (asynchronous)

DATABASE MIRRORING

role switching

automatic (requires a witness)

DATABASE MIRRORING

role switching

manual

DATABASE MIRRORING

failover clusteringhow it works

stop service

stop service

wait service

stop service

wait service

start service

Public

Shared Storage

failover clusteringhow it works

what commonly mentioned

Public

Shared Storage

failover clusteringhow it works

AD/DNS

WHYdo we even care

domain and DNS administrators

we need to speak to the

SQL Server 2012Availability Groups

Failover Clustering

Database Mirroring+

let’s talk about Availability Groupsin the context offailover clustering

Nodea server that is a member of a cluster

Nodea server that is a member of a cluster

Resourcea hardware, service or an entity that is hosted on a cluster

basic building block in a cluster

physical resource

Resource

storage

http://www.flickr.com/photos/peterajohnston/709441949/sizes/o/in/photostream/

network

server nodes

virtual resourceResource

virtual resourcevirtual server name

virtual IP address

virtual computer object

Resource

virtual resourcevirtual server name

virtual IP address

virtual computer object

Resource

a combination of resources that are managed as a UNIT

GroupResource

http://www.flickr.com/photos/alainbachellier/53004367/sizes/l/in/photostream/

GroupResource

GroupResource

GroupResource

moving a clustered resource from one node to another

Failover

reliance of a resource on another resource

Dependencies

*the minimum number of members of a deliberative assembly necessary to conduct the business of that group

Quorum

“majority vote wins”

Quorum

Hardware Requirements

Hardware Requirements

demo

http://www.mssqltips.com/webcast2.asp?id=105

Next Steps

Q & AQuestions