1. All the things you need to know before setting up AlwaysOn Michael Steineke SQL & BI Solution Lead Enterprise Architect Concurrency, Inc.

2. Terminology and Architecture  AlwaysOn  Marketing name for the high availability features in SQL Server  Includes  Fail over Cluster Instances (FCI)  Availability Groups (AG)  Windows Server Failover Clustering (WSFC)  All of AlwaysOn uses WSFC

3. High Availability vs. Disaster Recovery  High Availability  Generally same site  Quick Recovery  Disaster Recovery  Separate Site  Slower Recovery

4. Site to Site Considerations  How far apart are they?  What is the connectivity between sites?  Type of connection  Size of connection  Latency of connection

5. Networking  Server to server connectivity  Ports to open on Firewalls  TCP Ports 1433 & 1434 or specific SQL ports  AG Endpoint – tcp 5022  IP Addresses  DNS Names & IP Addresses  Servers, Cluster Name, AGs

6. Windows Clustering  What do I need to know as a DBA?  Management  Windows Failover Cluster Manager  PowerShell  Windows Domain  Joined  Authentication  SQL Server needs to run as a Domain Account  Connectivity  DNS Names and SQL Instances  Availability Group Listener  Ports  Quorum

7. Why do I care about Quorum?  Quorum Controls if the Cluster in Online  Majority of votes  What can vote?  Shared Disk  Servers – Active, Passive or Witness  File Share – Witness  Manual Voting override is available  In Multi-Site configurations you need to decide where the voting members are located

8. Windows Server Version & Clustering  Windows Server 2012 R2  Many useful updates to clustering  Dynamic Quorum  Cluster automatically controls Voting  Adjusts the vote weight of each node  Allows for Last Man Standing  Network Resiliency  Key to making sure the Cluster is healthy

9. Cluster Network Objects  Computers in AD  AD OU  Permissions  Cluster and Listener Objects in AD

10. OU Delegation  Create an OU and Delegate to the Cluster Account

11. SQL Server Version Comparison SQL 2012 Enterprise  Multiple Node FCI  Multi-Subnet Clusters  AG’s – 5 Copies of Data  4 Secondaries Total  2 Synchronous  Up to 4 Asynchronous  2 Automatic Failover Targets  Readable Secondaries SQL 2014 Enterprise  Multiple Node FCI  Multi-Subnet Clusters  AG’s – 8 Copies of Data  7 Secondaries  2 Synchronous  Up to 7 Asynchronous  2 Automatic Failover Targets  Readable Secondaries  Azure Replica  Backup to Azure  Site Survivability for Read Intent

12. FCI or AG?  If you need MSDTC, AGs don’t support MSDTC  AGs require separate Disk for each Instance  AGs can fail from node to node faster than FCI  Synchronous AGs require transactions to commit(log harden) on both servers  AG Secondaries can do workload  Backup & Read-only Answer – It depends on your needs You might want to combine them!

13. MSDTC  In Windows 2008 and later you either Create a clustered instance of the MSDTC resource for EVERY SQL Server instance /Group that requires its functionality or DO NOT CLUSTER MSDTC at all  View msdtc mappings  msdtc -tmMappingView *

14. Availability Group Setup  Shared Backup location  Permissions on share  Full on SQL Server Account

15. Multiples – Instances, AGs  You can have multiple AGs in an instance  Listeners are tied to AG  Multiple Instances  Each AG needs different ports for the endpoints  AG’s on Private Network

16. Multi-subnet  DNS  Client App connectivity  https://blogs.msdn.microsoft.com/alwaysonpro/2015/12/01/improve d-multisubnet-listener-behavior-with-newly-released-sql-client- provider-in-net-4-6-1/ https://blogs.msdn.microsoft.com/alwaysonpro/2015/12/01/improve d-multisubnet-listener-behavior-with-newly-released-sql-client- provider-in-net-4-6-1/  JDBC - https://msdn.microsoft.com/en- us/library/gg558121(v=sql.110).aspxhttps://msdn.microsoft.com/en- us/library/gg558121(v=sql.110).aspx  Azure Listener  https://blogs.msdn.microsoft.com/alwaysonpro/2014/03/31/use- readintent-routing-with-azure-alwayson-availability-group-listener/ https://blogs.msdn.microsoft.com/alwaysonpro/2014/03/31/use- readintent-routing-with-azure-alwayson-availability-group-listener/

17. Enabling AGs

18. What you need before the Wizard  Network Names  Cluster name  Listener Name  Firewall Rules/ports open  Listener  AG  IP Addresses  Each Server  Cluster Name  Each Listener  Active Directory  Permissions or Objects staged  Servers in OU  File System  Location of DB Files  Shared Backup Location

19. Useful Reference Links  SQL AlwaysOn Team Blog  http://blogs.msdn.com/b/sqlalwayson/ http://blogs.msdn.com/b/sqlalwayson/  SQL Server Customer Advisory Team  http://blogs.msdn.com/b/sqlcat/ http://blogs.msdn.com/b/sqlcat/  SQL Server 2014 Technet Reference  http://technet.microsoft.com/en-US/sqlserver/dn135309 http://technet.microsoft.com/en-US/sqlserver/dn135309  SQL High Availability on MSDN  http://social.msdn.microsoft.com/Forums/en-US/home?forum=sqlhadr http://social.msdn.microsoft.com/Forums/en-US/home?forum=sqlhadr  Failover Cluster Guide to Quorum  https://technet.microsoft.com/en-us/library/cc770620(WS.10).aspx https://technet.microsoft.com/en-us/library/cc770620(WS.10).aspx  Prestage Computer Objects in AD  https://technet.microsoft.com/en-us/library/dn466519.aspx https://technet.microsoft.com/en-us/library/dn466519.aspx  MSDTC  https://blogs.msdn.microsoft.com/alwaysonpro/2014/01/15/msdtc-recommendations-on-sql-failover-cluster/ https://blogs.msdn.microsoft.com/alwaysonpro/2014/01/15/msdtc-recommendations-on-sql-failover-cluster/  AGs on Private Network  https://blogs.msdn.microsoft.com/alwaysonpro/2013/11/01/configure-availability-group-to-communicate-on-a-dedicated-network/ https://blogs.msdn.microsoft.com/alwaysonpro/2013/11/01/configure-availability-group-to-communicate-on-a-dedicated-network/  SQL 2016 Changes to AGs  https://blogs.technet.microsoft.com/dataplatforminsider/2015/12/15/enhanced-always-on-availability-groups-in-sql-server-2016/ https://blogs.technet.microsoft.com/dataplatforminsider/2015/12/15/enhanced-always-on-availability-groups-in-sql-server-2016/

20. Thanks!  msteineke@concurrency.com  www.michaelsteineke.com  Twitter @MSteineke