[PVE-User] Question on SAN file system

[CDR]

I want to create a system with a central SAN where all ten VM's leave,
and three or more Proxmox servers around. So if one dies the next one
can start the virtual machine, or I can move it from server to server
and possibly do Vmotion (move the virtual machines without stopping
them).
I already created a SAN with Openfiler, but I am unsure about one
thing, if all the Proxmox server are using it, then what file system
needs to be used.
Can somebody help?