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David Barbarin

SQLSaturday #546 Porto – Troubleshooting scenarios with availability groups

By | Database management, Technology Survey | No Comments

J-1 before the next SQL Saturday 2016 in Portugal. I usually promote this event in France but this time this is for SQL Server Portuguese community. I will have the chance to talk about SQL Server AlwaysOn and troubleshooting scenarios. It will be also a good opportunity to meet portuguese people like Niko Neugebauer (@NikoNeugebauer), André Batista (@klunkySQL) and many others. Moreover, Porto is definitely a beautiful city and a good way to finish the summer…

 
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David Barbarin

SQL Server 2016 : Basic availability groups may fit to your HA needs

By | Database Administration & Monitoring | No Comments

In this blog let’s talk about SQL Server and availability groups in standard Edition. I had some customer questions about existing limitations and this is a good opportunity to review them on this blog post. First of all, let’s say that Microsoft has already documented the restrictions here and from my side, I already written a blog post on the subject at the time of the CTP version of SQL Server 2016. In the meantime,…

 
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David Barbarin

SQL Server AlwaysOn: new services packs and new diagnostic capabilities

By | Database Administration & Monitoring | No Comments

As you certainly know, the SQL Server 2014 SP2 has been released by Microsoft with some interesting improvements that concern SQL Server AlwaysOn and availability groups feature. In fact, all of them are also included into SQL Server 2012 SP3 and SQL Server 2016 (update 24.09.2016: not yet released with SQL Server 2016). Among all fixes and improvements that concern AlwaysOn, I would like to focus on those described in the Microsoft KB3173156 and KB3112363. But in this…

 
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David Barbarin

SQL Server 2016 AlwaysOn: Direct seeding and backup considerations

By | Database Administration & Monitoring | No Comments

As promised in my prior blog post, we’ll talk now about direct seeding feature and backups. We found an interesting LIMIT_CONCURRENT_BACKUPS value for current state of the hadr_automatic_seeding_state_transition event. As said last time, this value is meaningful by itself. So let’s try to perform a backup while the database is concerned by an active seeding session. In fact, my backup was blocked (as I supposed) and here what I found from the sys.dm_tran_locks and sys.dm_exec_requests…

 
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David Barbarin

SQL Server 2016 AlwaysOn: Direct seeding and performance considerations

By | Database Administration & Monitoring, Development & Performance | No Comments

This blog post follows the previous one about new direct seeding feature shipped with SQL Server 2016. As a reminder, I had some doubts about using direct seeding with large databases because log stream is not compressed by default but I forgot the performance improvements described into the Microsoft BOL. I also remembered to talk about it a couple of months ago in this blog post. So let’s try to combine all the things with the…

 
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David Barbarin

SQL Server 2016 AlwaysOn: distributed availability groups

By | Database Administration & Monitoring | No Comments

This time, I will talk about distributed availability groups. What’s that? In short, a group of availability groups. Sounds good right? But in which cases may we need such architecture? Firstly, let’s say that distributed availability groups will run on the top of two distinct availability groups meaning that they reside on two distinct WSFCs with their own quorum and voting management. Referring to the Microsoft documentation here, we may think that this new feature…

 
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David Barbarin

SQL Server 2016 AlwaysOn: Add DBs in AGs with direct seeding

By | Database Administration & Monitoring | No Comments

In this blog I would like to talk about two new features shipped with SQL Server 2016 for AlwaysOn availability groups. The first one concerns the new direct seeding capability and the seconde one introduces distributed availability groups (DAG). I will talk about the second one in a next blog post. First of all, let’s talk about direct seeding.  At the first glance, this feature seems very interesting because it simplifies a lot the process of adding…

 
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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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