The document discusses the AlwaysOn feature in SQL Server 2012, highlighting its capabilities for high availability (HA) and disaster recovery (DR) with support for up to five replicas. It details various backup solutions, including log shipping, replication, and mirroring, while noting that AlwaysOn provides automatic failover and configuration requirements such as Windows clustering. Additional considerations include settings for read-only access, backup options, and prerequisites for implementation.

1. AlwaysOn
In SQL Server 2012
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2. Terminologies
 High Availability (Planned and Unplanned)
 Disaster Recovery
 Recovery Time Objective (RTO)
 Recovery Point Objective (RPO)
 Budget

3. Solutions in SQL Server
 Backup and Restore
 Log Shipping
 Replication
 Mirroring
 SQL Cluster
 AlwaysOn
 Mix and Third parties

4. Backup and Restore
 Can lose data
 Inexpensive Solution for DR
 No HA

5. Log Shipping
 HA , DR
 No Automatic Failover but automate the process of backup and restore
 Database Level
 Inexpensive solution

6. Log Shipping

7. Replication
 Database , Object level
 No automatic failover
 Can use as Load balance
 HA , DR

8. Replication

9. Mirroring
 HA , DR
 Automatic failover (need witness server – optional)
 Read-only database for secondary

10. Mirroring

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. SQL Cluster

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. AlwaysOn

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.  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.  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. 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. Q&A
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