New answers tagged high-availability
Always On is not synonymous with (Always On) Availability Groups and instead is more a marketing term to describe a suite of Microsoft High Availability technologies (which I argue is at best ambiguous). The term actually started out as "Always On" (note the space) a long time ago as a pure marketing term (see my graphic as an example), but with the release ...
AGs are a lot more like a mix of mirroring and clustering than log shipping. Clustering would let you have multiple instances that fail over from one node to another node, but the nodes and disks are all absolutely distinct and only one instance runs at a time (though you can then load up other instances on the same set of nodes and make it more ...
Firstly, having 4 separate 2 node clusters with one FCI deployment in each seems to me to be a little extreme. The second model you describe does not really make sense to me. Instead of either deployment I would suggest running 2 Clusters of 4 nodes (you would need a witness for each) and consider one node in each as a dedicated failover node (i.e. that you ...
Your existing configuration of HAProxy -> PGBouncer -> PGServer approch is better. And that only works. Here is the reason: HAProxy redirects connection to different servers. this results in MAC address change in the database connection. So if PGBouncer is above HAProxy, each time the connections in the pool gets invalidated because of MAC address change.
Your only valid options would be transactional replication. No changes since your downstream version is 2008 R2. When dealing with features like AGs, it generally is same MAJOR version of SQL Server.
You can take log backup on any nodes (Primary/Secondary) irrespective of its availability mode. This is what MSDN has to say about this in Active Secondaries: Backup on Secondary Replicas (AlwaysOn Availability Groups): BACKUP DATABASE supports only copy-only full backups of databases, files, or filegroups when it is executed on secondary replicas. ...
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