SQL Server AlwaysOn is the new high availability and disaster recovery solution of the SQL Server "Denali". "Using AlwaysOn businesses can achieve increased application availability for their mission critical applications and get higher returns on their high availability investments through better utilization of hardware resources," explained Balasubramanian.
AlwaysOn also increases productivity and lowers TCO by greatly simplifying high availability deployment and management.
Key Features of AlwaysOn Availability Group
- Multi database failover
- Multiple secondaries (A secondary is conceptually similar to a Mirror in Database Mirroring)
- Max of 4 secondaries
- Synchronous and asynchronous data movement
- Support for 2 synchronous secondaries for additional data protection
- Built in compression and encryption of transport
- Automatic, Manual and Forced Failover
- Flexible failover policy
- Automatic Page Repair
- Active Secondary
- Readable secondary
- Secondary backup
- Automatic application redirection using virtual name
- Configuration Wizard for simplified deployment
- AlwaysOn Dashboard
- System Center Integration
- Automation using Powershell
- Rich diagnostic infrastructure
- DMV, Perfmon Counter, Xevents etc…
Key Features of AlwaysOn Failover Cluster Instance
- Native support for multi-site clustering across subnets enable DR using failover cluster instances
- Flexible Failover Policy
- Providing new failure detection mechanism using sp_server_diagnostics
- Customer Configurable failure condition level for more granular control on failover
- Better diagnostics
- SMB support enabling consolidation of more than 26 instances
- Support TEMPDB on local drive
- AlwaysOn Failover Cluster Instance can be a part of an AlwaysOn Availability Group
Database Availability and Instance Availability using AlwaysOn
- AlwaysOn Availability Group is the new feature in SQL Server AlwaysOn that provides availability forapplication database(s). Availability Group provides a rich set of options that gives the flexibility to configure a high availability environment that can meet the SLA's of the various applications in your environment. The feature also comes with a set of options that allows utilization of your secondaries. Apart from these options there is complete integration with management studio and Powershell that makes deployment and management of Availability Group extremely simple.
- AlwaysOn Failover Cluster Instance enhances the existing SQL Server Failover Clustering feature and provides availability for the entire instance. AlwaysOn provides a richer set of capabilities that will increase instance availability and addresses a number of existing pain points.
For more information on AlwaysOn please go to the AlwaysOn Resource Center.