We have an ESX cluster with 4 host (HP DL380 G7/G8s)and host our production VMs on a fibre attached SAN. This all works perfectly, no problems. 

One of our backup methods is to Veeam production VMs to local storage on one of our ESX host (for the likes of a SAN failure). The other 3 ESX host have little to no local storage. In a DR situation where the SAN is unavailable for some reason, is it possible to have machines hosted on the 3 ESX host that do not have local storage, using the storage on our ESX host with the local storage? I am thinking that this is what Vsan achieves, but to be honest don't completely understand how it all clicks together. 

Thanks