According to the SAP HANA high availability for Azure virtual machines documentation, for SAP HANA database high availability, you need to deploy three VMs. One VM is for the SAP HANA system replication (HSR) primary instance, one VM is for the SAP HANA HSR secondary instance, and one VM is for the SAP Business One components.
So, to answer your question, you need three VMs to build high availability for SAP HANA Business One.
You can refer to these document https://learn.microsoft.com/en-us/azure/sap/workloads/sap-hana-availability-overview
https://learn.microsoft.com/en-us/azure/sap/workloads/sap-high-availability-architecture-scenarios
Also, these articles provide a good overview of using SAP HANA in Azure:
- Manual installation of single-instance SAP HANA on Azure VMs
- Set up SAP HANA system replication in Azure VMs
- Back up SAP HANA on Azure VMs
It's also a good idea to be familiar with these articles about SAP HANA:
- High availability for SAP HANA
- FAQ: High availability for SAP HANA
- Perform system replication for SAP HANA
- SAP HANA 2.0 SPS 01 What’s new: High availability
- Network recommendations for SAP HANA system replication
- SAP HANA system replication
- SAP HANA service auto-restart
- Configure SAP HANA system replication
Beyond being familiar with deploying VMs in Azure, before you define your availability architecture in Azure, we recommend that you read Manage the availability of Windows virtual machines in Azure.
I hope this helps. Let me know if you have any further questions.
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