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David Barbarin

SQL Server AlwaysOn: is my database ready for failover?

By | Database Administration & Monitoring | No Comments

In this blog post I just want to clarify values that we may find from the is_failover_ready column of the sys.dm_hadr_database_replica_cluster_states DMV. A couple of days ago, I had an interesting discussion with one of my customers during which he explained he was not confident about the availability group state after facing some unavailability issues. The main source of uncertainty was the result from the following query that he used to check if everything was…

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David Barbarin

MVP Data Platform renewed and next SQL Saturday event at Paris

By | Technology Survey | No Comments

The last 1th April 2016, I got my 6th MVP Data Platform renewal (not an april’s fool for sure). This is definitely a good news and I would like to thanks again Microsoft for its interest. So the story continues and I want to share with you the next sessions I will have the opportunity to animate in the next SQL Saturday in Paris on the 25th and 26th June 2016.   First session (precon)…

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David Barbarin

SQL Server AlwaysOn: when a listener becomes the cluster and vice versa

By | Database Administration & Monitoring, Database management | No Comments

Let’s talk about a funny story that concerns an interesting issue that I faced a couple of months ago at one of my customers. Initially, the problem concerned only the creation of an availability group listener but after deleting the related availability group, he noticed quickly that the deletion failed but even more strange, he noticed that the virtual network name related to the listener corresponded to the virtual computer object of the cluster itself….

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David Barbarin

SQL Server AlwaysOn and availability groups : session timeout parameter

By | Database Administration & Monitoring | 12 Comments

Have you ever faced to timeout issues with SQL Server availability groups? If you take a look at the timeout parameters for an availability group, you will find a plenty of configuration settings. Indeed, you have timeout parameters for the availability group itself, for the replicas and for cluster itself as well. Well …a lot of parameters in order to deal with timeout issues. In fact, some of them can be very helpful regarding the…

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David Barbarin

SQL Server 2016 – availability groups and gMSAs

By | Database management | No Comments

This blog post will probably not concern customers where either password policy change rules are not defined for service accounts or Kerberos authentication is not used. But I’m sure that the number of these customers has decreased over at least the last decade. By the way, this is what I can notice at different customer places. But before beginning with group managed services let’s introduce managed services … Why using managed services (MSAs) against traditional…

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David Barbarin

SQL Server 2016 : availability groups and performance improvements

By | Development & Performance, Hardware & Storage | No Comments

During the last SQL Saturday in Paris, I had the opportunity to co-present the new SQL Server 2016 features and one of my topic concerned the availability group’s enhancements. I mentioned the replication throughput improvement but without giving more details and this is the idea of this blog post. First of all, let’s remind that the network throughput is part of the synchronous replication process and it is directly tied to the application transaction performance….

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David Barbarin

SQL Server 2016 : availability groups with no domain dependencies

By | Database Administration & Monitoring | No Comments

Are you aware about the new features of the next Windows version? Currently we’re in TP3 and during my investigation, I was very happy to see the new features for Windows clustering (cf. this blog post from Microsoft). By reading this article we can see: Workgroup Clusters: Clusters with nodes which are member servers / workgroup (not domain joined) If you remember, Microsoft had introduced Active Directory-Detached Cluster feature with Windows 2012 but the dependency…

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David Barbarin

SQL Server AlwaysOn : readable secondary replicas and index rebuild online vs offline

By | Database Administration & Monitoring | 4 Comments

A couple of weeks ago, I was involved in a discussion on the French forum developpez.com about SQL Server AlwaysOn and availability groups, index strategies and the impact on the readable secondary replicas. During this discussion, one of the forum member stated that rebuilding an index online had less impact than rebuilding an index offline on a readable secondary replica but I disagree with this affirmative. Is it really true? Let’s verify in this blog…

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David Barbarin

SQL Server AlwaysOn: number of databases and the hadr worker pool

By | Database Administration & Monitoring | No Comments

Often, when I’m in charge to implement an SQL Server AlwaysOn infrastructure with availability groups, customers ask me if it exists some best practices and recommendations about the maximum number of databases in an availability group planning. In fact, we have to keep in mind the relation between databases and the SQL Server worker pool in this architecture. Remember that the SQL Server AlwaysOn and availability group feature is an extension of the SQL Server…

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David Barbarin

SQL Server 2016 : availability groups and the new clustered columnstore index support

By | Hardware & Storage | No Comments

This blog post is focused on the new supportability of clustered columnstore index on the high- availability read-only replicas. Others studies are available here: New database issue level detection for automatic failover Potential features in standard edition Automatic failover enhancements New load balancing features with read-only replicas After reading some improvements from the columnstore index feature side, I was very surprised to see the following section:   Clustered columnstore indexes are now supported on AlwaysOn…

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