AlwaysOn Availability Groups unable to query against readable secondary replica database: Wait Type HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING

Recently a customer reported an interesting issue, while querying against recently added readable replica, SELECT statement is shown as suspended and session is shown as waiting on HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING Here is a simple way to reproduce the scenario Now on current primary replica, change one of the remote replica to readable However, running a SELECT Statement…

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Configure SQL Server Failover Cluster Instance on Azure Virtual Machines with MSDTC

Configure SQL Server Failover Cluster Instance If you are running a SQL Server Failover Cluster Instance on premises and looking to migrate to Azure, you might be a little intimidated. This architecture is a bit complex because it uses quite a few different technologies all working together. My goal is to help clarify the pieces…

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Domain Independent Cluster and Availability Group

What is a Domain Independent Cluster? Did you know that you can have a Windows cluster that is a domain independent cluster and run a SQL Server Availability Group on top of it?  The technology has been around for a while, but a lot of DBAs are not aware of it.  Why?  All the glory…

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Read-Scale Availability Group Setup

What is a Read-Scale Availability Group? A Read-Scale Availability Group is a Clusterless Availability Group.  It’s sole purpose and design is to scale out a read workload.  More importantly is what it is not.  It is NOT a High Availability or Disaster Recovery solution.  Since this design has no cluster under it, you lose things…

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MSDTC Supported Configurations

The MSDTC Configuration Conundrum MSDTC configuration is not as straight forward as you might think. It’s a different choice if you are using a local MSDTC, clustered MSDTC, on-premises, Azure, Failover Cluster, or Availability Group. Every one of those variables leads you down a different path with different choices. The goal of this article is…

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How to Upgrade an AG Cluster to Windows 2016

Starting in Windows Server 2012 R2 you now have a way to upgrade a cluster to Windows 2016.  The best part is it’s not an OS upgrade, but a rebuild.  The magic is that you can join a Windows 2016 server to a Windows 2012 R2 cluster.  You can upgrade your cluster with as little…

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SQL Server 2017 Read-Scale Availability Groups

SQL Server 2017 was recently launched, having multiple new features. One of these included something called “Read-Scale Availability Groups”. There was a good bit of discussion about this feature and one of the feedback items was that the details in Docs was very light. I hope to rectify the minimal amount of information through this…

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SQL Server Workgroup Cluster FCM Errors

Background One of the new features of SQL Server 2016 is the ability to use SQL Server with Failover Cluster in a workgroup rather than joined to Active Directory. When working with SQL Server and Failover Clustering in a workgroup, many of the abilities that are normally used with Active Directory are no longer available,…

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Finding Which Connections Have Been Read Only Routed

This is a follow up to my first post Finding What Availability Group Listeners Applications Are Using To Connect, where a question was posed about knowing which connections have been read only routed. Background Information SQL Server Availability Groups allow for something called “Read Only Routing” which allows for severs that are currently a secondary…

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Finding What Availability Group Listeners Applications Are Using To Connect

Background Information While on site helping with AlwaysOn Availability Groups, it was tasked to a DBA to meet with all of the application owners and figure out what listener they were currently using in their connection strings. The DBA looked over at me and said, “I wish there was a DMV that showed me connection…

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