[PVE-User] cluster numbers

[Alessandro Briosi]

Hi all,
I have a question about cluster quorum (proxmox 4).

I currently have a 3 host cluster with shared storage (gluster).

I have an old machine which I could use as a backup/service in case of
some host failure, though adding this server to the cluster would make
the cluter composed of 4 hosts which could possibly lead to a split
brain in case of 2 hosts separated from the other 2 hosts (remote but
possible).

Should the cluster always be composed by an odd number of hosts?

I'm not using HA so if I move some VM from one host to the other I'm
aware of what the current situation is.

In case of a split brain am I able to say which cluster part has quorum?

Thank you,
Alessandro