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

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.

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

Common Setup Today Database Mirroring Log Shipping

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

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

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.

Windows Server Pre-Reqs Windows Server 2008 and above KB 976097 Supports SQL Server Failover Cluster Instances with AlwaysOn Availability Groups KB 2494036 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: http://technet.microsoft.com/en-us/library/cc731002(WS.10).aspx

Quorum Configuration Quorum: need majority of votes to operate and avoid split brain Two-Steps process: Select nodes to vote (KB 2494036) 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

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

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

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.

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

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

New Topology Reports Backups A Synchronous Data Movement Asynchcronous Data Movement

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

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