Hello @JohnWeb , Apologies for delay in response to your query.
Azure Site Recovery is not a high availability solution rather a BSCDR solution. So, I don’t think this is the best forum for your question.
You may want to inquire about availability sets, availability zones, and proximity placement groups if you plan to deploy FTP solution in IAAS infrastructure.
https://learn.microsoft.com/en-us/azure/architecture/example-scenario/infrastructure/iaas-high-availability-disaster-recovery
Also, there is an old discussion on MSDN forum - https://social.msdn.microsoft.com/Forums/azure/en-US/6dbcbf74-d820-41c1-8c3f-32ddf011d539/setting-up-a-high-availability-sftp-server-in-azure?forum=WAVirtualMachinesforWindows the suggestions might be helpful.
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