1. AlwaysOn, an Early bird Overview
Tobias Ternström
Senior Program Manager Lead, SQL Engine

2. Our organization SQL Server RDBMS Team Applications and Components
External Apps
Excel
Project
Server
Content
Management
Server
MOM
MS CRM
Outlook
Visual Studio
Dynamics
LCS
Commerce
Server
Oslo
Exchange
Biztalk Server
Sharepoint
DPM
SQL Replication
SQL Management
Tools
SQL Reporting
Services
SQL Analysis
Services
SQL Integration
Services
SQL Server RDBMS Team
Connectivity
MDAC
ODBC, OLE-DB
SNAC
ODBC, OLE-DB
EDM
Ado.Net
SQL Client
JDBC
App Platform T-SQL Language, Data-Tier Application Model, Types, Libraries
SQL Engine
Query Processor Query Opimization & Execution
Storage & Admin Storage Engine, DR etc.
High Availability Mirroring, Clustering, etc.

3. Failover Cluster Instances
AlwaysOn Solution
Availability Groups
Failover Cluster Instances
Non-Shared Storage
Database Level HA Protection
Active Secondaries
Shared Storage
Instance Level HA Protection

4. Common Setup Today
Database Mirroring
Log Shipping

5. AlwaysOn Availability Groups
AlwaysOn Availability Groups is a new feature that enhances and combines database mirroring and log shipping capabilities
Flexible
Integrated
Efficient
Multi-database failover
Multiple secondaries
Total of 4 secondaries
2 synchronous secondaries
1 automatic failover pair
Synchronous and asynchronous
data movement
Built in compression and encryption
Automatic and manual failover
Flexible failover policy
Automatic Page Repair
Application failover using virtual name
Configuration Wizard
Dashboard
System Center Integration
Rich diagnostic infrastructure
Replication publisher failover
Supported with Contained Database, FileStream, FileTable, Service Broker
Active Secondary
Readable Secondary
Backup from Secondary
Automation using power-shell

6. Application Failover Primary Secondary Secondary Primary Secondary
Availability Groups Listener allow applications to failover seamlessly to any secondary
Application reconnects using a virtual name after a failover to a secondary
ServerA
ServerB
ServerC HR DB HR DB HR DB
AG_HR
HR_VNN
Primary
Secondary
Primary
Secondary
Secondary
Application retry during failover
Connect to new primary once
failover is complete
and the listener is online
-server HR_Listener;-catalog HRDB

7. Availability Group Architecture
Windows Server Failover Cluster
Database
Active Log
Synchronization
Database
Active Log
Synchronization
Availability Group uses Windows Server Failover Cluster (WSFC) for
WSFC Common Microsoft Availability Platform
SQL Server AlwaysOn Failover cluster instances
SQL Server AlwaysOn Availability Group
Microsoft Hyper-V
Microsoft Exchange
Built-in WSFC workloads (e.g. file share, NLB, etc) and third party workloads
Inter-node health detection,
Failover coordination,
Primary health detection,
Distributed data store for settings and state,
Distributed change notifications
© 2010 Microsoft Corporation.   Microsoft Materials - Confidential.  All rights reserved.

8. Windows Server Pre-Reqs
Windows Server 2008 and above KB
Supports SQL Server Failover Cluster Instances with AlwaysOn Availability Groups KB
Supports configuring optimal quorum with non-automatic failover targets
All nodes should be in the same AD domain
To create WFSC cluster user running creation must have:
Domain account
Administrator on all machines
Have Create Computer objects and Read All Properties rights in AD
Detailed Article:

9. Quorum Configuration
Quorum: need majority of votes to operate and avoid split brain
Two-Steps process:
Select nodes to vote (KB )
1 vote if node’s that host a replica that is currently:
Primary  (if primary is an FCI include all possible owner nodes for that FCI)
An auto failover target if the primary is also configured for auto failover
0 votes for rest of nodes
Select the quorum type:
Odd number of votes, use “Node Majority”
Even number of votes, add a witness by either:
Adding an additional witness node and use “Node Majority”
Using “Node and File Share Majority” with a protected file share (blog with details)
Re-evaluate and adjust quorum after manual failover outside automatic target

10. AlwaysOn Active Secondary
IT efficiency and cost-effectiveness is critical for businesses
Idle hardware is not an option anymore
AlwaysOn Active Secondary enables efficient utilization of high availability hardware resources thereby improving overall IT efficiency
Active Secondary can be utilized for
Balancing read-only workloads
Offloading Backup Operations

11. Active Secondary – Making Secondary Readable
Primary
Failover
Secondary
SQLservr.exe
SQLservr.exe
Secondary
Primary
InstanceA
InstanceB
DB2
DB1
DB2
DB1
Reports
Reports
Readable secondary allow offloading read queries to secondary
Close to real-time data, latency of log synchronization impact data freshness

12. Readabale Secondary – Data Latency
DB1
Log Capture
Log Capture
Network
DB1
Primary
Log Recieve
Secondary
Log Pool
Commit
Redo Thread
Log Cache
Log Cache
Redo Pages
Log Flush
Log Hardened
DB1 Log
DB1 Data
Acknowledge Commit
DB1 Log
DB1 Data
Secondary read is always behind primary during transaction activity
Changes for a transaction are visible on the readable secondary only after REDO thread processes the COMMIT log record. No dirty reads are allowed on RS.

13. Read-Only Client Connectivity
Read-Only client connection behavior determined by Availability Replica Option + ApplicationIntent Property
ApplicationIntent is a connection property
Replica option determines whether a replica is enabled for read access when in a secondary role
Read-Only Routing enables redirection of client connection to new secondary on role change
Enable seamless redirection of application connection across replicas without manual intervention

14. Active Secondary: Enabling Backup On Secondary
R/W workload
Primary
Backups
Secondary
Backups can be done on any replica of a database
Backups on primary replica still works
Log backups done on all replicas form a single log chain
Database Recovery Advisor makes restores simple

15. New Topology Reports Backups A Synchronous Data Movement
Asynchcronous Data Movement

16. Additional Topology Examples
AlwaysOn provides the flexibility of different HA configurations
Shared Storage, regional and geo secondaries A A
Direct attached storage local, regional and geo secondaries
Synchronous
Data Movement
Asynchcronous Data Movement

17. For attending this session and PASS SQLRally Nordic 2011, Stockholm
THANK YOU!
For attending this session and PASS SQLRally Nordic 2011, Stockholm