Failed to gzip archive.
gzip: /var/www/discourse/public/backups/default/MYDISCOURSE-2025-04-12-033421-v20250321143553.tar.gz: No space left on device
I checked disk space, and I have 60GB.
/var/www/discourse/public was on the data disk where there was plenty of space, but I think I screwed up an update (as no-one else here seems to have complained), and /var/www/discourse/public/backups had a symlink to the old/OS disk, where there was only 7GB free.
Too me ages to work out, hope this will help someone else to get there faster.