---
title: "Add a secondary replica to an availability group"
description: "Learn how to add a secondary replica to an Always On availability group using either Transact-SQL (T-SQL), PowerShell, or the Availability Group Wizard in SQL Server Management Studio (SSMS)."
ms.custom: "seodec18"
ms.date: "05/18/2016"
ms.prod: sql
ms.reviewer: ""
ms.technology: high-availability
ms.topic: conceptual
helpviewer_keywords: 
  - "Availability Groups [SQL Server], availability replicas"
  - "Availability Groups [SQL Server], configuring"
ms.assetid: 6669dcce-85f9-495f-aadf-7f62cff4a9da
author: MashaMSFT
ms.author: mathoma
---
# Add a secondary replica to an Always On Availability Group
[!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md](../../../includes/appliesto-ss-xxxx-xxxx-xxx-md.md)]
  This topic describes how to add a secondary replica to an existing Always On availability group by using [!INCLUDE[ssManStudioFull](../../../includes/ssmanstudiofull-md.md)], [!INCLUDE[tsql](../../../includes/tsql-md.md)], or PowerShell in [!INCLUDE[ssCurrent](../../../includes/sscurrent-md.md)].  

  
##  <a name="PrerequisitesRestrictions"></a> Prerequisites and Restrictions  
  
-   You must be connected to the server instance that hosts the primary replica.  
  
 For more information, see [Prerequisites, Restrictions, and Recommendations for Always On Availability Groups &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/prereqs-restrictions-recommendations-always-on-availability.md).  

##  <a name="Security"></a> Security  
  
###  <a name="Permissions"></a> Permissions  
 Requires ALTER AVAILABILITY GROUP permission on the availability group, CONTROL AVAILABILITY GROUP permission, ALTER ANY AVAILABILITY GROUP permission, or CONTROL SERVER permission.  

[!INCLUDE[Freshness](../../../includes/paragraph-content/fresh-note-steps-feedback.md)]

##  <a name="SSMSProcedure"></a> Using SQL Server Management Studio  
 **To add a replica**  
  
1.  In Object Explorer, connect to the server instance that hosts the primary replica, and expand the server tree.  
  
2.  Expand the **Always On High Availability** node and the **Availability Groups** node.  
  
3.  Right-click the availability group, and select one of the following commands:  
  
    -   Select the **Add Replica** command to launch the Add Replica to Availability Group Wizard. For more information, see [Use the Add Replica to Availability Group Wizard &#40;SQL Server Management Studio&#41;](../../../database-engine/availability-groups/windows/use-the-add-replica-to-availability-group-wizard-sql-server-management-studio.md).  
  
    -   Alternatively, select the **Properties** command to open the **Availability Group Properties** dialog box. The steps for adding a replica in this dialog box are as follows:  
  
        1.  In the **Availability Replicas** pane of the dialog box, click the **Add** button. This creates and selects a replica entry in which the blank Server Instance field is selected.  
  
        2.  Enter the name of a server instance that meets the prerequisites for hosting an availability replica.  
  
         To add an additional replicas, repeat the preceding steps. When you are done specifying replicas, click **OK** to complete the operation.  
  
##  <a name="TsqlProcedure"></a> Using Transact-SQL  
 **To add a replica**  
  
1.  Connect to the instance of [!INCLUDE[ssNoVersion](../../../includes/ssnoversion-md.md)] that hosts the primary replica.  
  
2.  Add the new secondary replica to the availability group by using the ADD REPLICA ON clause of the ALTER AVAILABILITY GROUP statement. The ENDPOINT_URL, AVAILABILITY_MODE, and FAILOVER_MODE options are required in an ADD REPLICA ON clause. The other replica options- BACKUP_PRIORITY, SECONDARY_ROLE, PRIMARY_ROLE, and SESSION_TIMEOUT-are optional. For more information, see [ALTER AVAILABILITY GROUP &#40;Transact-SQL&#41;](../../../t-sql/statements/alter-availability-group-transact-sql.md).  
  
     For example, the following [!INCLUDE[tsql](../../../includes/tsql-md.md)] statement creates a new replica to an availability group named `MyAG` on the default server instance hosted by `COMPUTER04`, whose endpoint URL is `TCP://COMPUTER04.Adventure-Works.com:5022'`. This replica supports manual failover and asynchronous-commit availability mode.  
  
    ```  
    ALTER AVAILABILITY GROUP MyAG ADD REPLICA ON 'COMPUTER04'   
       WITH (  
             ENDPOINT_URL = 'TCP://COMPUTER04.Adventure-Works.com:5022',  
             AVAILABILITY_MODE = ASYNCHRONOUS_COMMIT,  
             FAILOVER_MODE = MANUAL  
             );  
    ```  
  
##  <a name="PowerShellProcedure"></a> Using PowerShell  
 **To add a replica**  
  
1.  Change directory (**cd**) to the server instance that hosts the primary replica.  
  
2.  Use the **New-SqlAvailabilityReplica** cmdlet.  
  
     For example, the following command adds an availability replica to an existing availability group named `MyAg`. This replica supports manual failover and asynchronous-commit availability mode. In the secondary role, this replica will support read access connections, allowing you to offload read-only processing to this replica.  
  
    ```  
    $agPath = "SQLSERVER:\Sql\PrimaryServer\InstanceName\AvailabilityGroups\MyAg"  
    $endpointURL = "TCP://PrimaryServerName.domain.com:5022"  
    $failoverMode = "Manual"  
    $availabilityMode = "AsynchronousCommit"  
    $secondaryReadMode = "AllowAllConnections"  
  
    New-SqlAvailabilityReplica -Name SecondaryServer\Instance `   
    -EndpointUrl $endpointURL `   
    -FailoverMode $failoverMode `   
    -AvailabilityMode $availabilityMode `   
    -ConnectionModeInSecondaryRole $secondaryReadMode `   
    -Path $agPath  
    ```  
  
    > [!NOTE]  
    >  To view the syntax of a cmdlet, use the **Get-Help** cmdlet in the [!INCLUDE[ssNoVersion](../../../includes/ssnoversion-md.md)] PowerShell environment. For more information, see [Get Help SQL Server PowerShell](../../../relational-databases/scripting/get-help-sql-server-powershell.md).  
  
 **To set up and use the SQL Server PowerShell provider**  
  
-   [SQL Server PowerShell Provider](../../../relational-databases/scripting/sql-server-powershell-provider.md)  
  
##  <a name="FollowUp"></a> Follow Up: After Adding a Secondary Replica  
 To add a replica for an existing availability group, you must perform the following steps:  
  
1.  Connect to the server instance that is going to host the new secondary replica.  
  
2.  Join the new secondary replica to the availability group. For more information, see [Join a Secondary Replica to an Availability Group &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/join-a-secondary-replica-to-an-availability-group-sql-server.md).  
  
3.  For each database in the availability group, create a secondary database on the server instance that is hosting the secondary replica. For more information, see [Manually Prepare a Secondary Database for an Availability Group &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/manually-prepare-a-secondary-database-for-an-availability-group-sql-server.md).  
  
4.  Join each of the new secondary databases to the availability group. For more information, see [Join a Secondary Database to an Availability Group &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/join-a-secondary-database-to-an-availability-group-sql-server.md).  
  
##  <a name="RelatedTasks"></a> Related Tasks  
 **To manage an availability replica**  
  
-   [Join a Secondary Replica to an Availability Group &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/join-a-secondary-replica-to-an-availability-group-sql-server.md)  
  
-   [Remove a Secondary Replica from an Availability Group &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/remove-a-secondary-replica-from-an-availability-group-sql-server.md)  
  
-   [Configure Read-Only Access on an Availability Replica &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/configure-read-only-access-on-an-availability-replica-sql-server.md)  
  
-   [Change the Availability Mode of an Availability Replica &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/change-the-availability-mode-of-an-availability-replica-sql-server.md)  
  
-   [Change the Failover Mode of an Availability Replica &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/change-the-failover-mode-of-an-availability-replica-sql-server.md)  
  
-   [Change the Session-Timeout Period for an Availability Replica &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/change-the-session-timeout-period-for-an-availability-replica-sql-server.md)  
  
-   [Change the Session-Timeout Period for an Availability Replica &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/change-the-session-timeout-period-for-an-availability-replica-sql-server.md)  
  
## See Also  
 [ALTER AVAILABILITY GROUP &#40;Transact-SQL&#41;](../../../t-sql/statements/alter-availability-group-transact-sql.md)   
 [Overview of Always On Availability Groups &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/overview-of-always-on-availability-groups-sql-server.md)   
 [Creation and Configuration of Availability Groups &#40;SQL Server&#41;](../../../database-engine/availability-groups/windows/creation-and-configuration-of-availability-groups-sql-server.md)   
 [Use the Always On Dashboard &#40;SQL Server Management Studio&#41;](../../../database-engine/availability-groups/windows/use-the-always-on-dashboard-sql-server-management-studio.md)   
 [Monitor Availability Groups &#40;Transact-SQL&#41;](../../../database-engine/availability-groups/windows/monitor-availability-groups-transact-sql.md)