Just a thought,
Have you considered network bandwidth increase, as your traffic will increase by 50%.

About getting rid of the arbiter, you may check the following:
https://lists.ovirt.org/pipermail/users/2017-July/083022.html

Best Regards,
Strahil Nikolov

On Apr 16, 2019 11:02, Leo David <leoalex@gmail.com> wrote:
Hi Everyone,
I have wrongly configured the main gluster volume ( 12 identical 1tb ssd disks, replica 3 distributed-replicated, across 6 nodes - 2 per node ) with arbiter one. 
Oviously I am wasting storage space in this scenario with the arbiter bricks, and I would like to convert the volume to non-arbitrated one, so having all the data evenly spreaded across all the disks.
Considering the the storage is being used by about 40 vms in production, what would it be the steps, or is there any chance to change the volume type to non-arbitrated on the fly and then rebalance ?
Thank you very much !