After screwing my infra with the update to 4.2 (probably a bad manipulation), i am planning a rebuild of the entire infra. First i want to replace my NFS storage with a glusterfs storage. All documentation tell me that i need 3 hosts.. but for the moment i only have 2 but planning to had more later. 

So does it make sense to start with 2 hosts and use glusterfs as the storage domain(lets says with a replicate of two with all its limitations). 

If it make sense, 

1- what is the best way to do it.

2- how hard will it be to had the 3rd host when available and make it  replica 2+arbiter.

Also in a setup where i have 3 hosts (replica 2+arbiter) does all the 3 hosts can run users vm?

Thanks for your inputs.

Carl