I am running vSphere Essentials Plus in a datacenter with 3 hosts. Each host has several virtual machines already installed. Each host server has local storage installed in a RAID 10 that was used as the data store for each. We recently installed a SAN and migrated most of the vm's to it. We have a license for vSphere Storage Appliance and wanted to use it to create a cluster with the local storage of each host. Would I be better off investing more money into the SAN or trying to create the cluster with the storage appliance license? Can storage appliance be installed with virtual machines on the disks already?