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What are the requirements for a distributed availability group?
SQL Server version and edition requirements for distributed availability groups. Distributed availability groups in SQL Server 2017 or later can mix major versions of SQL Server in the same distributed availablity group. The AG containing read/write primary can be the same version or lower than the other AGs participating in the distributed AG.
How are distributed availability groups scale out readable replicas?
A distributed availability group can scale out readable replicas in two ways: You can use the primary replica of the second availability group in a distributed availability group to create another distributed availability group, even though the database is not in RECOVERY.
Which is better Windows clustering or distributed Ag?
While Windows clustering now supports rolling OS upgrades, its much easier to do a distributed AG, because the clusters are independent of each other and have no impact on each other. The second is that its very easy to fail back and forth between these distributed availability groups.
Can a distributed Ag contain the same read / write primary?
The AG containing read/write primary can be the same version or lower than the other AGs participating in the distributed AG. The other AGs can be the same version or higher. This scenario is targeted to upgrade and migration scenarios.
How does always on availability group with mixed SQL Server work?
It was an enhanced version of Database Mirroring technology but it allowed people to create groups of databases that can automatically failover together. Moreover, AG Listener gets all client connection requests and directs them to the appropriate availability replica. No need to update DNS records in case of a failover anymore!
How to implement SQL Server 2016 always on distributed?
Step #1: Setup and Implement SQL Server 2016 Always On Distributed Availability Groups Production DR IP Subnet: 172.16.0.0/16 IP Subnet: 192.168.0.0/24 Name: AG_DC1 Name: AG_DC2 Listener: AG_DC1_LISTENER Listener: AG_DC2_LISTENER Listener IP: 172.16.0.114 Listener IP: 192.168.0.116
What makes a WSFC cluster a distributed availability group?
A distributed availability group spans multiple availability groups, each on its own underlying WSFC cluster, and a distributed availability group is a SQL Server-only construct. This means the WSFC clusters that house the individual availability groups can have different major versions of Windows Server.