AlwaysOn

SQL Server 2016: Distributed availability groups and Cross Cluster migration

How to migrate an environment that includes availability groups from one Windows Failover Cluster to another one? This scenario is definitely uncommon and requires a good preparation. How to achieve this task depends mainly of your context. Indeed, we may(…)

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

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(…)

SQL Server AlwaysOn: troubleshooting improvements with new service packs

As promised in my latest blog, I will talk about improvements in the detection of the availability group replication latency. As a reminder, replication latency between high(…)

SQL Server AlwaysOn: new services packs and new diagnostic capabilities

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.

SQL Server 2016 AlwaysOn: Direct seeding and backup considerations

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(…)

SQL Server 2016 AlwaysOn: Direct seeding and performance considerations

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(…)

SQL Server AlwaysOn: is my database ready for failover?

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(…)

SQL Server AlwaysOn : the registry is also important for availability groups

A couple of months ago, we experienced with my colleague Nathan Courtine a weird issue at one of our customers. This issue concerned an AlwaysOn availability group and more precisely to the WSFC cluster layout. I(…)

Windows failover cluster 2016 : new site awareness feature

After my first two blogs about cloud witness and domain-less dependencies features shipped with Windows Server 2016, it’s time to talk about another pretty cool feature of the WSFC : site awareness that will also benefit to our(…)

Availability groups : readable secondary replicas and impact on the storage layer

Do read-only capabilities of an availability group have a performance impact for databases? The quick response is yes but let’s see why in this blog post. First of all, when we want to use our secondary replicas as read-only, we(…)