@Aurelien thanks I didn't know I had to set the bug to new, I will do it from now on.

I dindt change the osd-devices configuration I used the default configuration and added an other ceph unit (130TB) after deployment with:

juju add-unit ceph-osd
juju run-action --wait ceph-osd/3 add-disk osd-devices=/dev/sdc. 

the space available in each unit is
geoint@maas:~$ juju ssh 0
ubuntu@PowerEdge-9R0DH13:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev             63G     0   63G   0% /dev
tmpfs            13G  3.0M   13G   1% /run
/dev/sda2       274G   49G  212G  19% /
tmpfs            63G     0   63G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs            63G     0   63G   0% /sys/fs/cgroup
/dev/sda1       511M  7.9M  504M   2% /boot/efi
/dev/loop2       56M   56M     0 100% /snap/core18/1988
tmpfs           1.0M     0  1.0M   0% /var/snap/lxd/common/ns
/dev/loop7       73M   73M     0 100% /snap/lxd/19766
/dev/loop4       69M   69M     0 100% /snap/lxd/19823
/dev/loop6       33M   33M     0 100% /snap/snapd/11402
/dev/loop1       56M   56M     0 100% /snap/core18/1997
/dev/loop8       33M   33M     0 100% /snap/snapd/11588
tmpfs            13G     0   13G   0% /run/user/1000


geoint@maas:~$ juju ssh 1
ubuntu@PowerEdge-9R0FH13:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev             63G     0   63G   0% /dev
tmpfs            13G  3.1M   13G   1% /run
/dev/sda2       274G   45G  215G  18% /
tmpfs            63G     0   63G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs            63G     0   63G   0% /sys/fs/cgroup
/dev/sda1       511M  7.9M  504M   2% /boot/efi
/dev/loop0       56M   56M     0 100% /snap/core18/1988
tmpfs           1.0M     0  1.0M   0% /var/snap/lxd/common/ns
/dev/loop7       73M   73M     0 100% /snap/lxd/19766
/dev/loop8       69M   69M     0 100% /snap/lxd/19823
/dev/loop6       33M   33M     0 100% /snap/snapd/11402
/dev/loop1       56M   56M     0 100% /snap/core18/1997
/dev/loop9       33M   33M     0 100% /snap/snapd/11588
tmpfs            13G     0   13G   0% /run/user/1000

geoint@maas:~$ juju ssh 2
ubuntu@PowerEdge-9R0CH13:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev             63G     0   63G   0% /dev
tmpfs            13G  3.1M   13G   1% /run
/dev/sda2       274G   52G  208G  20% /
tmpfs            63G     0   63G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs            63G     0   63G   0% /sys/fs/cgroup
/dev/sda1       511M  7.9M  504M   2% /boot/efi
/dev/loop0       56M   56M     0 100% /snap/core18/1988
tmpfs           1.0M     0  1.0M   0% /var/snap/lxd/common/ns
/dev/loop7       73M   73M     0 100% /snap/lxd/19766
/dev/loop4       69M   69M     0 100% /snap/lxd/19823
/dev/loop6       33M   33M     0 100% /snap/snapd/11402
/dev/loop1       56M   56M     0 100% /snap/core18/1997
/dev/loop8       33M   33M     0 100% /snap/snapd/11588
tmpfs            13G     0   13G   0% /run/user/1000


geoint@maas:~$ juju ssh 3
ubuntu@NX3240-4XF2613:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            7.6G     0  7.6G   0% /dev
tmpfs           1.6G  1.6M  1.6G   1% /run
/dev/sda2       137G  8.2G  122G   7% /
tmpfs           7.6G     0  7.6G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           7.6G     0  7.6G   0% /sys/fs/cgroup
/dev/sda1       511M  7.9M  504M   2% /boot/efi
/dev/loop0       56M   56M     0 100% /snap/core18/1988
/dev/loop1       70M   70M     0 100% /snap/lxd/19188
tmpfs           1.0M     0  1.0M   0% /var/snap/lxd/common/ns
/dev/loop4       71M   71M     0 100% /snap/lxd/19647
/dev/loop5       33M   33M     0 100% /snap/snapd/11402
/dev/loop2       56M   56M     0 100% /snap/core18/1997
/dev/loop6       33M   33M     0 100% /snap/snapd/11588
tmpfs           1.6G     0  1.6G   0% /run/user/1000

ubuntu@NX3240-4XF2613:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            7.6G     0  7.6G   0% /dev
tmpfs           1.6G  1.6M  1.6G   1% /run
/dev/sda2       137G  8.2G  122G   7% /
tmpfs           7.6G     0  7.6G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           7.6G     0  7.6G   0% /sys/fs/cgroup
/dev/sda1       511M  7.9M  504M   2% /boot/efi
/dev/loop0       56M   56M     0 100% /snap/core18/1988
/dev/loop1       70M   70M     0 100% /snap/lxd/19188
tmpfs           1.0M     0  1.0M   0% /var/snap/lxd/common/ns
/dev/loop4       71M   71M     0 100% /snap/lxd/19647
/dev/loop5       33M   33M     0 100% /snap/snapd/11402
/dev/loop2       56M   56M     0 100% /snap/core18/1997
/dev/loop6       33M   33M     0 100% /snap/snapd/11588
tmpfs           1.6G     0  1.6G   0% /run/user/1000

and ceph status is 
geoint@maas:~$ juju ssh ceph-mon/2 sudo ceph status
  cluster:
    id:     457c2212-7412-11eb-bb51-ffc0149f2d99
    health: HEALTH_ERR
            1 full osd(s)
            18 pool(s) full
 
  services:
    mon: 3 daemons, quorum juju-191a8d-1-lxd-0,juju-191a8d-0-lxd-0,juju-191a8d-2-lxd-0 (age 5w)
    mgr: juju-191a8d-0-lxd-0(active, since 6w), standbys: juju-191a8d-1-lxd-0, juju-191a8d-2-lxd-0
    osd: 5 osds: 5 up (since 6w), 5 in (since 6w); 51 remapped pgs
    rgw: 1 daemon active (juju-191a8d-0-lxd-1)
 
  task status:
 
  data:
    pools:   18 pools, 99 pgs
    objects: 488.92k objects, 1.8 TiB
    usage:   5.3 TiB used, 118 TiB / 123 TiB avail
    pgs:     290276/1466763 objects misplaced (19.790%)
             51 active+clean+remapped
             48 active+clean
 
Connection to 192.168.221.12 closed.