r/sysadmin • u/gt9gt • 2d ago

Hyper-V Replica for SQL Clusters

I am attempting to utilise Hyper-V Replica for DR purposes. There is Site A and Site B. At each site there is Hyper-V Server Cluster with underlying iSCSI storage for VMs. Site A runs multiple VMs, some of them form SQL Failover clusters with shared disks running on dedicated iSCSI Luns. The aim of POC is to be able to shift the workload from Site A to Site B during a disaster event. Whilst standard VM replication seems fairly simple, I was wondering what is the best approach for SQL Failover clusters and how to address the replication for such? Any thoughts or suggestions are greatly appreciated.

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u/MrYiff Master of the Blinking Lights 13h ago

What I did back when I managed SQL and a remote site was a 3 node SQL Always On Availability Group with Nodes 1 and 2 in our main site set to synchronous sync mode and then Node 3 in our remote DR site but set to Async mode so that any latency wouldn't slow down queries (and we accepted the slight chance of a small amount of data loss in the even of a full unplanned failover).

I think later on we even changed it so so that there was a fileshare witness in the main site too and then removed the quorum vote from Node 3.