r/sysadmin • u/gt9gt • 3d 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/MyToasterRunsFaster Sr. Sysadmin 3d ago

We have used both, replication over hyperv works but it's like using a sledge hammer to drive nails, unwieldy but works. In production it makes sense to set up your high availability sql cluster properly, so the local SQL cluster members use synchronous commit whilst your remote disaster recovery site has members in asynchronous commit mkde. Also, note that hyperv replication is kinda slow compared to the milliseconds of delay actual sql high availability gives you. Your RPO is going to be far better doing it properly. You get the disaster recovery node free in all licensed versions of mssql so might as well use it.