To add a fully replicated node you need to reduce the replica count to 2 and add new brick to the volume so that it becomes replica 3. Reducing replica count by removing a brick from replica / arbiter cannot be done from UI currently and this has to be done using gluster CLI.
AFAIR, there was an issue where vm's were going to paused state when reducing the replica count and increasing it to 3. Not sure if this still holds good with the latest release.
Any specific reason why you want to move to full replication instead of using an arbiter node ?
To move arbiter role to a new node you can move the node to maintenance , add new node and replace old brick with new brick. You can follow the steps below to do that.and remove the arbiter node (Also a way to move the arbiter role to the new node, If needed)
- Move the node to be replaced into Maintenance mode
- Prepare the replacement node
- Prepare bricks on that node.
- Create replacement brick directories
- Ensure the new directories are owned by the vdsm user and the kvm group.
- # mkdir /rhgs/bricks/engine
- # chmod vdsm:kvm /rhgs/bricks/engine
- # mkdir /rhgs/bricks/data
- # chmod vdsm:kvm /rhgs/bricks/data
- Run the following command from one of the healthy cluster members:
- # gluster peer probe <new_node>
- add the new host to the cluster.
- Add new host address to gluster network
- Click Network Interfaces sub-tab.
- Click Set up Host Networks.
- Drag and drop the glusternw network onto the IP address of the new host.
- Click OK
- Replace the old brick with the brick on the new host
- Click the Bricks sub-tab.
- Verify that brick heal completes successfully.
- In the Hosts tab, right-click on the old host and click Remove.
- Clean old host metadata
- # hosted-engine --clean-metadata --host-id=<old_host_id> --force-clean