virtual techdays INDIA │ September 2011 High Availability - A Story from Past to Future Balmukund Lakhani │ Technical Lead – SQL Support, Microsoft | |

virtual techdays INDIA │ September 2011 A B O U T M E… Working with SQL Technology since 2001 (almost 10 years) Currently working as Technical Lead with Microsoft SQL Support team Premier Field Microsoft ERP Onsite Ramco Systems Ramco Systems Ramco Systems Team Blog – Personal Blog – Active Participant in MSDN SQL Forums.

 Why High Availability?  The Past… Quick Recap  Log-Shipping  Database Mirroring  Failover Clustering  Replication  Database Snapshot  The Future… In Depth  High Availability and Disaster Recovery Solution in SQL Server “Denali” virtual techdays INDIA │ September 2011 S E S S I O N A G E N D A

virtual techdays INDIA │ September 2011 Why High Availability?

virtual techdays INDIA │ September 2011 Mission Critical High Availability Solution 5 Meets mission critical high availability SLA Integrated Efficient Flexible

virtual techdays INDIA │ September 2011 High Availability Solutions… The past !

virtual techdays INDIA │ September 2011 L O G – S H I P P I N G Copy Perform Backups Copy and Restore Backups Raise Alerts Primary Database Monitor Database Secondary Database Copy and Restore Backups

virtual techdays INDIA │ September 2011 DATABASE MIRRORING Mirror Principal Witness Log ApplicationSQL Server Data Log 3>2>3 Mirror is always redoing – it remains current Commit

O T H E R T E C H O N O L I G E S virtual techdays INDIA │ September 2011

virtual techdays INDIA │ September 2011 O T H E R T E C H O N O L I G E S Replication Database Snapshots Failover Clustering

E X I S T I N G T O P O L O G Y virtual techdays INDIA │ September 2011 Log Shipping Database Mirroring

virtual techdays INDIA │ September 2011 High Availability Solutions… The Future!

virtual techdays INDIA │ September 2011 AlwaysOn Availability Groups (Future of High Availability) AlwaysOn Availability Groups is a new feature that enhances and combines database mirroring and log shipping capabilities  Multi-database failover  Multiple secondaries  Total of 4 secondaries  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  File-stream replication  Replication publisher failover Flexible Integrated Efficient  Active Secondary  Readable Secondary  Backup from Secondary  Automation using power-shell

virtual techdays INDIA │ September 2011 Demo – Setting up AlwaysOn Configure AlwaysOn Availability Group

virtual techdays INDIA │ September 2011 What we did in demo? Replace Database Mirroring and Log Shipping with Availability Group Advantages: – One integrated solution for HA and DR – Groups of databases failing over together – Multiple secondaries – Listener for Client Connectivity – Backup on secondary – Readable secondary Restrictions: – No delayed apply on the secondary

virtual techdays INDIA │ September 2011 P r e – r e q u i s i t e s All SQL servers (including the secondary in the DR site) in the same Windows domain. One Windows Server Failover Cluster spreads over the primary and DR sites All the databases must be in FULL recovery model 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: KB – Supports SQL Server Failover Cluster Instances with AlwaysOn Availability Groups KB – Supports configuring optimal quorum with non-automatic failover targets

AA AA AA virtual techdays INDIA │ September 2011 N E W T O P O L O G Y

virtual techdays INDIA │ September 2011 N E W T O P O L O G Y A D V A N T A G E Better SLAs – Multiple no data loss secondaries – Better data loss protection for DR secondaries through continuous replication – Faster failover to DR secondaries through virtual name failover Easier deployment/management – Unified solution – Simple deployment – Unified dashboard – Rich diagnostics – Centralized management of client connection topology – Multi-DB failover

virtual techdays INDIA │ September 2011 SQL Server AlwaysOn – BoS (Backup on Secondary)

virtual techdays INDIA │ September 2011 Database Mirroring Backups Backups are only allowed on Primary Secondary cannot be leveraged for backups Backup Workload impacts production Server

virtual techdays INDIA │ September 2011 Active Secondary: Offloading Backup Backups are allowed on any replica. – Synchronous or asynchronous secondaries – Primary backups still work Backup workload does not impact production server. Highly requested feature. Log backups done on all replicas form a single log chain Recovery Advisor makes restores simple

virtual techdays INDIA │ September 2011 Restrictions, cautions, and gotchas Differential backups are not supported on secondary Only Copy-only full backups are supported on secondary – The only distinction is the differential bitmap clearing Advisable for backups to be stored centrally

virtual techdays INDIA │ September 2011 Demo - Backup on Secondary Backup on Secondary & Use them to create new Replica

virtual techdays INDIA │ September 2011 SQL Server AlwaysOn – Readable Secondary

virtual techdays INDIA │ September 2011 Readable Secondary DB2 DB1 SQLServr.exe InstanceA DB2 DB1 Primary Secondary Database Log Synchronization InstanceB Reports

virtual techdays INDIA │ September 2011 Readable Secondary Data Latency Log Cache DB1 DB1 Log DB1 Primary Replica Log Capture Log Recieve DB1 Data Network Redo Thread Redo Pages DB1 Log Page Updated Log Harden Log Flush Commit Acknowledge Commit Log Pool DB1 Data

virtual techdays INDIA │ September 2011 Demo – Readable Secondary Reading Data From Secondary & Creating Secondary Routing

AA AA AA AA virtual techdays INDIA │ September 2011 Reports Backups Synchronous Data Movement Asynchcronous Data Movement F i n a l T o p o l o g y

virtual techdays INDIA │ September 2011 S U M M A R Y SQL Server AlwaysOn is a comprehensive high availability solution Better application availability, Higher return on investment and Simplified deployment and management AlwaysOn Availability Group provide flexibility in HA configuration

virtual techdays INDIA │ September 2011 RELATED CONTENT in VTD Sep 29 th 2011 – DBA Track  Monitoring Performance in Cloud for SQL Azure Applications  Vinod Kumar  3:00pm - 4:00pm  Managing SQL Server Made Easy - Features and Concepts  Amit Banerjee  4:15pm - 5:15pm

virtual techdays THANKS │ September 2011 Please do give your Feedback, Complete evaluation at the end of this session. You could also write to be at : │ twitter.com/blakhanihttp:// twitter.com/blakhani