Per unique requirements necessary for working with the VMware IO/Filter framework and Azue VMware Solution (AVS) a different minumum number of hosts are required to install and uninstall JetStream DR for AVS software.
Installation
When installing the software, it is necessary to create an AVS cluster which can be done using the minumum required number of three hosts. The number of hosts can be increased or decreased as necessary after deployment.
Uninstallation
When uninstalling, however; a minium of four hosts are required. The additional host is necessary to allow the cluster to enter maintenance mode. (AVS has a mandatory anti-affinity rule that prevents three NSX-T appliances from running on the same ESXi host. Adding a fourth host to the cluster allows the NSX-T appliances to be shifted across hosts as necessary allowing the cluster to enter maintenance mode for uninstallation.)