I'm no expert, but I saw one on TV once. And I have stayed at a Holiday Inn Express before. Caveats aside....
If you are going to have a small total number of vms in this cluster, than 1 vm per lun is manageable. I would not want to do that once that number got above 15-20.(personal preference).
Benefits> Simplicity of design 1 vm=1 lun, best performance i/o wise.
Cons> More luns to manage, does not scale well for large # of vm's, may have different luns sizes if you tailor to each vm.
Multiple vm's per lun:
Benefits > Easier to manage the luns (less of them), simpler to design lun size and standardize (make storage admins happy), probably have space to expand vm if needed, easier to scale as total # of vm's increase, you could also have different luns sizes within a cluster.
Cons > Probably be somewhat less efficent in terms of space utilization (a few percentage points depending on how you plan/implement), possible to hit some performance limit of underlying storage system.
To me the main criteria for this is what is more critical to you, performance or manageability. Most servers that run as vm's do not have high i/o requirements which usually suggests multiple vm's per lun.
Having fewer luns to manage I think is valuable. You should first look at the i/o requirements of your servers and then think about what you expect the environment to look like in a year or 2-3.
If you are not going to add more than a few servers and you have some high i/o servers, then maybe you want to go 1 vm per lun. Or maybe have some luns with 1 vm, and others with multiple.
Max luns = 256
