You
I have 2 TB of photos on one external drive and that is my entire backup strategy.
ChatGPT
That is not a backup, it is a second copy of a single point of failure. The rule that has survived thirty years is 3-2-1: three copies, on two kinds of media, one offsite.
You
ChatGPT
For 2 TB the practical version is a local NAS for the nightly copy and object storage for the weekly one. At current prices the cloud leg costs roughly 10 to 12 EUR a month for that volume, which is the part people balk at and the only part that survives a fire or a theft.
You
How do I know the backups actually work?
ChatGPT
Restore something on a schedule. An untested backup is a belief, not a backup. Pick a random directory once a quarter, restore it to a scratch location, and compare checksums:
restic restore latest --target /tmp/verify --include /photos/2019/07
diff <(cd /photos/2019/07 && sha256sum * | sort) \
<(cd /tmp/verify/photos/2019/07 && sha256sum * | sort)