Hi,
Here is the OPM 7.1 and UM 7.1 Documentation. It lists the VMware software requirement, but no hardware requirement.
https://library.netapp.com/ecm/ecm_download_file/ECMLP2549573
Virtual appliance requirements The VMware ESXi server on which the virtual appliance is deployed must meet minimum resource requirements. The following versions of VMware ESXi are supported: • ESXi 5.5 and updates • ESXi 6.0, 6.0 U1, and 6.0 U2 The following versions of VMware vSphere are supported: • VMware vCenter Server 5.5 and updates • VMware vCenter Server 6.0, 6.0 U1, and 6.0 U2 Important: The VMware ESXi server must use the same time as the NTP server so that the virtual appliance functions correctly. Synchronizing the VMware ESXi server time with the NTP server time avoids a time failure.
http://mysupport.netapp.com/documentation/productlibrary/index.html?productID=61373
Virtual appliance requirements The VMware ESXi server on which the virtual appliance is deployed must meet minimum resource requirements. The following versions of VMware ESXi are supported: • ESXi 5.5 and updates • ESXi 6.0, 6.0 U1, and 6.0 U2 See the Interoperability Matrix for the complete and most current list of supported ESXi versions. mysupport.netapp.com/matrix The following versions of vSphere are supported: • VMware vCenter Server 5.5 and updates • VMware vCenter Server 6.0, 6.0 U1, and 6.0 U2 System requirements for deploying the Unified Manager virtual appliance.
You are correct - during upgrade, you will have some downtime for UM and OPM, but the ONTAP cluster itself will continue to run without any interruption caused by the UM/OPM upgrade.
Julia