Why do you use minio for image serving ? There are much better ways to do so. Nextcloud, Immich, Photoprism and others…

The Omada probably not. But many other tp-link routers support it, especially the low spec ones. I mean, if we are getting to something more performant and feature rich, there are probably much better options, like Turris Omnia, some Microtik stuff and many other.

but what is nice, many tp-link hw can run regular openwrt, which is way better than the thing they provide…

something running openWRT. I for example have a Turris Omnia, which is running their own fork of openwrt. https://www.turris.com/en/omnia/overview/

Exactly, you can end up with inconsistent DB state. Only possible filesystem level solution is take a LVM/btrfs/zfs snapshot and copy the DB files from there, but at that point, the dump is much easier and more convenient.

docker exec nextcloud-mariadb-1 /usr/bin/mariadb-dump --defaults-extra-file=/backup/.mylogin.cnf -u root --single-transaction --quick --all-databases |gzip > /mnt/mysql/backup/nc${NUM}_dump.gz

You are welcome