The obvious weakness is that we are still reliant on our ESXi hosts, also located in the server room. How do people get around this? I was thinking of purchasing a small server, locating it elsewhere and installing ESXi with the idea it can be fired up and our VMs imported from the VEEAM backup in the event of losing both the SAN and the ESXi Hosts. Is this the best way of doing this? If so what sort of compatibility issues might I come across (processor?)
Theoretically you shouldn't have any, the guests don't care what they're on as long as it's ESXi and the host doesn't matter as long as drivers are all in place. But in reality it's no different to a physical server. You wouldn't have an identical physical box spare for every physical server so the same applies here. As long as other measures are in place like hotswap drives for the RAID arrays/SAN arrays, redundant power supplies etc you should be OK. Processors, mainboards, memory etc don't tell to fail so you don't need to keep those on hand so much. If they do it's usually down to external factors out of your hands. There's only so much you can prepare for. VEEAM is an awesome backup system.