Always on in SQL Server 2012


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The AlwaysOn Availability Groups feature is a high-availability and disaster-recovery solution that provides an enterprise-level alternative to database mirroring. Introduced in SQL Server 2012, AlwaysOn Availability Groups maximizes the availability of a set of user databases for an enterprise

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Always on in SQL Server 2012

  1. 1. AlwaysOnIn SQL Server 2012Fadi Abdulwahab – SharePoint Administrator - 4/2013
  2. 2. Terminologies High Availability (Planned and Unplanned) Disaster Recovery Recovery Time Objective (RTO) Recovery Point Objective (RPO) Budget
  3. 3. Solutions in SQL Server Backup and Restore Log Shipping Replication Mirroring SQL Cluster AlwaysOn Mix and Third parties
  4. 4. Backup and Restore Can lose data Inexpensive Solution for DR No HA
  5. 5. Log Shipping HA , DR No Automatic Failover but automate the process of backup and restore Database Level Inexpensive solution
  6. 6. Log Shipping
  7. 7. Replication Database , Object level No automatic failover Can use as Load balance HA , DR
  8. 8. Replication
  9. 9. Mirroring HA , DR Automatic failover (need witness server – optional) Read-only database for secondary
  10. 10. Mirroring
  11. 11. SQL Cluster HA Expensive solution ( HD , License ,..) Server level Include two nodes or more Required SAN Storage A/P , A/A ,A/A/P,… Need DR (Log shipping , Backup and Restore,..) No Load Balance ( Use Transactional Replication)
  12. 12. SQL Cluster
  13. 13. AlwaysOn New Feature in SQL Server 2012 Can have 5 replicas (one Primary and four secondary servers) HA , DR (enhancement for mirroring) and Read-only access Can be sync and async ( No acknowledgement ,minimize the transactions) No need for SAN storage (Not like SQL Cluster) Can deploy geographical Can use Secondary servers for backup and reporting access Automatic failover Types (Primary (R/W and send trans logs to secondary) and Secondary (R)
  14. 14. AlwaysOn
  15. 15.  Windows Cluster is required Interchangeable ( Transactions terminated) Failover can be ( Automatic , Manual and forced (possible data lose in case of async) (by commands) Support T-SQL and PowerShell Diff Backup not supported for secondary Secondary use snapshots to avoid any blocking Support page repair Client can connect direct , Ava group and Read-only routing
  16. 16.  Read-only settings ( No , Read –intent only , Yes) Database should be :  Not belong to any Ava. Group  Enable R/W  Enable Multi User mode  Full Recovery  Full backup  Not used by mirroring
  17. 17.  Automatic Failover (up to 2) (Required Sync) Sync (Up to 3) Need DNS and Static IP ( can be DHCP) Configuration (Full (same path – need backup ) – Join (Already restored) – skip (restore later When SQL user added to Primary the user must created in secondary (except if use contained databases – New feature in SQL Server 2012) Backup Options  Prefer (run on secondary except if primary not online)  Secondary only (Not support diff backup)  Primary only (support diff backup)  Any replica (based on factors)
  18. 18. Demo Prerequisites ( Windows Cluster , 2 instances at least) Configuration (Enable , Create Ava. Group and backup) Add/Remove databases … Add/Remove Replica… Suspended and resume… Dashboard and DMVs for monitoring
  19. 19. Q&AThis Child Camel price of 450,000 RS