An Always On availability group is a predefined collection of SQL Server relational databases that failover together when conditions trigger a failover in any one database, redirecting requests to a mirrored database on another instance in the same availability group. If you are using availability groups as your high availability solution, you can use a database in that group as a data source in an Analysis Services tabular or multidimensional solution. All of the following Analysis Services operations work as expected when using an availability database: processing or importing data, querying relational data directly (using ROLAP storage or DirectQuery mode), and writeback.

This topic serves as a reference page to all the various system objects that can be used when working with Always On availability groups.

This topic describes how to switch the HADR cluster context of an instance of [!INCLUDE[ssNoVersion](../../../includes/ssnoversion-md.md)] by using [!INCLUDE[tsql](../../../includes/tsql-md.md)] in [!INCLUDE[ssSQL11SP1](../../../includes/sssql11sp1-md.md)] and later versions. The *HADR cluster context* determines which Windows Server Failover Clustering (WSFC) cluster manages the metadata for availability replicas hosted by the server instance.

This topic describes the requirements and steps for clustering the Microsoft Distributed Transaction Coordinator (DTC) service for [!INCLUDE[ssHADR](../../../includes/sshadr-md.md)]. For additional information regarding distributed transactions and [!INCLUDE[ssHADR](../../../includes/sshadr-md.md)], see [Cross-Database Transactions and Distributed Transactions for Always On Availability Groups and Database Mirroring (SQL Server)](../../../database-engine/availability-groups/windows/transactions-always-on-availability-and-database-mirroring.md).

This topic describes how to configure the flexible failover policy for an Always On availability group by using [!INCLUDE[tsql](../../../includes/tsql-md.md)] or PowerShell in SQL Server. A flexible failover policy provides granular control over the conditions that cause [automatic failover](../../../database-engine/availability-groups/windows/failover-and-failover-modes-always-on-availability-groups.md) for an availability group. By changing the failure conditions that trigger an automatic failover and the frequency of health checks, you can increase or decrease the likelihood of an automatic failover to support your SLA for high availability.

Configuring [!INCLUDE[ssNoVersion](../../../includes/ssnoversion-md.md)] replication and Always On availability groups involves seven steps. Each step is described in more detail in the following sections.

This topic walks you through a complete configuration of a clustered DTC resource for a SQL Server Always On Availability Group. The complete configuration can take up to an hour to complete.

[!INCLUDE[ssHADR](../../../includes/sshadr-md.md)], the high availability and disaster recovery solution introduced in [!INCLUDE[sssql11](../../../includes/sssql11-md.md)], requires Windows Server Failover Clustering (WSFC). Also, though [!INCLUDE[ssHADR](../../../includes/sshadr-md.md)] is not dependent upon [!INCLUDE[ssNoVersion](../../../includes/ssnoversion-md.md)] Failover Clustering, you can use a failover clustering instance (FCI) to host an availability replica for an availability group. It is important to know the role of each clustering technology, and to know what considerations are necessary as you design your [!INCLUDE[ssHADR](../../../includes/sshadr-md.md)] environment.

This topic contains information about the using the FILESTREAM and FileTable features with [!INCLUDE[ssHADR](../../../includes/sshadr-md.md)] in [!INCLUDE[ssCurrent](../../../includes/sscurrent-md.md)].