Discourse-Upgrade schlägt wegen unzureichenden Speicherplatzes auf 25G-Droplet fehl

Installation
2 
root@DO-Discourse:/var/discourse# df -h
Dateisystem    Größe Benutzt Verf. B κατάgr. Eingehängt auf
udev            448M        0  448M   0% /dev
tmpfs            99M    1,1M   98M   2% /run
/dev/vda1        25G     18G  6,2G  75% /
tmpfs           491M        0  491M   0% /dev/shm
tmpfs           5,0M        0  5,0M   0% /run/lock
tmpfs           491M        0  491M   0% /sys/fs/cgroup
/dev/vda15      105M    9,2M   96M   9% /boot/efi
overlay          25G     18G  6,2G  75% /var/lib/docker/overlay2/d319d95263d87c2a75a4bc9a9f03a25ea7f6eb1f7bac687e7ae7d45522939dc0/merged
/dev/loop10      56M     56M     0 100% /snap/core18/2284
/dev/loop7       44M     44M     0 100% /snap/snapd/14978
/dev/loop5       62M     62M     0 100% /snap/core20/1361
/dev/loop2       68M     68M     0 100% /snap/lxd/22526
/dev/loop1       62M     62M     0 100% /snap/core20/1376
/dev/loop3       44M     44M     0 100% /snap/snapd/15177
/dev/loop4       56M     56M     0 100% /snap/core18/2344
/dev/loop6       68M     68M     0 100% /snap/lxd/22753
tmpfs            99M        0   99M   0% /run/user/0
root@DO-Discourse:/var/discourse#