SOS, how to use glusterfs ?

[seepine]

I has 3 ubuntu server with 40G, and i want to create a file cluster for use by k8s, providing more than 40G of storage space, and also ensuring that NFS services can be provided normally even if one of the servers goes down.

I have discovered GlusterFS and, according to the documentation, connected three servers now.

$ sudo gluster pool list
UUID                                    Hostname        State
7bb8e7e7-dfb8-4398-b229-79ebe26b6e15    192.168.100.101 Connected 
d307ea61-9b57-4464-91f1-e7c3907e9d1f    192.168.100.102 Connected 
d343f330-ac91-41b1-9d9d-4c28ce16fdd9    localhost       Connected 

$ sudo gluster peer status
Number of Peers: 2

Hostname: 192.168.100.101
Uuid: 7bb8e7e7-dfb8-4398-b229-79ebe26b6e15
State: Peer in Cluster (Connected)

Hostname: 192.168.100.102
Uuid: d307ea61-9b57-4464-91f1-e7c3907e9d1f
State: Peer in Cluster (Connected)

But I got some error when i create volume from the doc https://docs.gluster.org/en/latest/Administrator-Guide/Brick-Naming-Conventions/

export GDIR=/home/$USER/gdir
$ sudo gluster volume create myvolume replica 2 192.168.100.100:$GDIR 192.168.100.101:$GDIR 192.168.100.102:$GDIR force
volume create: myvolume : failed: Failed to create volume files

[seepine]

I create volume by replica 3, it can be work

export GDIR=/home/$USER/gdir
$ sudo gluster volume create myvolume replica 3 192.168.100.100:$GDIR 192.168.100.101:$GDIR 192.168.100.102:$GDIR force
volume create: myvolume: success: please start the volume to access data

$ sudo gluster volume start myvolume
volume start: myvolume: success

$ mkdir ./nas_dir
$ mount -t glusterfs 192.168.100.100:/myvolume ./nas_dir
$ echo "hello" > ./nas_dir/test.txt

But test.txt stored on 3 server and the final available space is still 40G, this is not the achievement i need.