Create Availability Group Fails With Error 35250 ‘Failed to join the database’

You can create an availability group using the New Availability Group wizard or using a series of transact-sql commands. A common failure can occur when attempting to create an availability group using either method. The error is as follows and is caused because the target primary and secondary replicas are unable to communicate: Msg 35250,…


Recovery On Secondary Lagging – Shared Redo Target

There are various reasons a secondary may not be keeping up (slow network, blocked redo worker by a long running query on a readable secondary, ….)   This post is going to focus on the shared redo target. You may not be aware but redo on a secondary involves a handshake with the primary.   You can…


How It Works: SQL Server AlwaysOn Lease Timeout

The LeaseTimeout controls the lease mechanism and when the lease expires there is a very high probability of a system wide event taking place.   Let me explain more and why I make this statement. Based in recent cases I needed to extend and clarify this post. http://blogs.msdn.com/b/psssql/archive/2012/09/07/how-it-works-sql-server-alwayson-lease-timeout.aspx Bob Dorr – Principal SQL Server Escalation Engineer


Configure Availability Group to Communicate on a Dedicated Network

SQL Server 2012 AlwaysOn Availability Groups uses a database mirroring endpoint for each SQL Server instance that hosts an availability group replica. The endpoint is used to communicate between the primary and the secondary replicas of the availability group. If a second NIC is installed on the primary replica and secondary replica of an availability group,…


Create Availability Group Listener Fails with Message 19471, ‘The WSFC cluster could not bring the Network Name resource online’

When trying to create an availability group listener, SQL Server may fail and report the following error: Create failed for Availability Group Listener ‘SQLCDB01Temp’. (Microsoft.SqlServer.Smo) The WSFC cluster could not bring the Network Name resource with DNS name ‘SQLCDB01Temp’ online. The DNS name may have been taken or have a conflict with existing name services,…


SQLPass 2013 Presentation "Enterprise High Availability with AlwaysOn Availability Groups [DBA-398-P]"

Presentation Description: AlwaysOn, the new SQL Server 2012 premier high availability solution, provides high availability and reliability by taking advantage of new and proven technology. Built on two pillars – SQL Server failover clustered instance (FCI) and SQL Server availability groups (AGs) – AlwaysOn is versatile and can be configured a variety of ways to…


Performing Transaction Log Backups using AlwaysOn Availability Group Read-Only Secondary Replicas – Part 1

This is the first post in a planned series of articles relating to SQL Server Transaction Log Backups of databases using a read-only secondary replica (ROSR).  With the introduction of ROSRs in SQL Server 2012, administrators can now perform full database (copy only) backups as well as transaction log backups on one of the secondary…


LooksAlive and IsAlive Implementation of Availability Groups failure_condition_level

AlwaysOn availability groups introduce the new flexible failover policy for SQL Server instance health monitoring for the AlwaysOn availability group resource.  Legacy clustered SQL Server utilized a LooksAlive that performed a lightweight check of the SQL Server process health. The legacy IsAlive connected to SQL Server and executed a simple query. AlwaysOn flexible failover policy offers…


Connect to SQL Server Using Application Intent Read-Only

  Once you have configured your SQL Server availability group for read-only routing (see blog ‘End to End – Using a Listener to Connect to a Secondary Replica (Read-Only Routing)’) you must install the SQL Native Access Client (SNAC) provider that supports application intent connections and you must write your application using the correct and…


End to End – Using a Listener to Connect to a Secondary Replica (Read-Only Routing)

Read-only routing refers to the ability of SQL Server to route incoming connections to an availability group listener to a secondary replica that is configured to allow read-only workloads. The following end to end steps demonstrate how to configure and use read-only routing to route read-intent listener connections to the secondary replica. This demo performs…