Objstorage volume size in staging environment is critical

On storage1.internal.staging.swh.network:

root@storage1:~# df -hT | awk 'NR==1 || /zfs/' | grep objects
Filesystem                Type      Size  Used Avail Use% Mounted on
data/objects              zfs        25T   23T  2.3T  91% /srv/softwareheritage/objects