My current hyperconverged environment is replicating data across all 3 servers.

I'm running critically low on disk space, and need to add space.

To that end, I've ordered 8x 800GB ssd drives, and plan to put 4 drives in 1 server, and 4 drives in the other.

What's my best option for reconfiguring the hyperconverged cluster, to change gluster storage away from Replica 3 to a Replica 2 / Arbiter model?

I'd really prefer not to have to reinstall things from scratch, but I'll do that if I have to.

My most important requirement is that I cannot have any downtime for my VMs (so I can only reconfigure 1 host at a time).