I know, that oVirt with Hosted Engine requires  a replica 3 glusterfs volume, but I'm using 4 nodes and  I would like to know if is possible to add it to the glusterfs engine volume.

Or should I always use 3, 5 and 7 hosts with hosted-engine? 

What I'm doing:

gluster volume add-brick engine server1:/gluster/engine/brick1 server2:/gluster/engine/brick1 server3:/gluster/engine/brick1 server4:/gluster/engine/brick1

Error:

volume add-brick: failed: Incorrect number of bricks supplied 4 with count 3

If I'm using replica 3 will not be possible, but how can I upgrade it? Adding 2 more nodes and upgrade to replica 5?

Thanks in Advance!

Best Regards

Gabriel Stein