Tarsnap is cozy

One use case: I don't like the idea of having any accounts at all which I log into without the aid of a password manager. That creates a bootstrapping problem - how am I supposed to log into Google Drive to get my Google Drive password? A prepaid keyfile-based model is one particularly robust way of solving this. You stick your e.g. 100 kB password database in there, print out and shred the keyfile, stick the printout in a fireproof safe, and be virtually certain that whatever you put in Tarsnap has been untouched however many years you come back to it later. Print it on archival paper with some silica gel packets and it might survive for millennia in your weird subterranean vampire family castle.

"The business won't survive that long." I'm not so sure. Its ongoing costs appear minimal, and it generates eye watering amounts of float. $5 paid today is >$200 fifty years from now when compounded at 8% real interest. That very fact makes it much more likely that Tarsnap actually will survive for those 50 years, which should make us more likely to trust it, which... You see where this is going. This is one of those things where aggressively pricing too close to the bare metal costs might actually be a bad thing to a very important subset of users. One might even make the argument that, if the margins are as good as I'm supposing they are, then depending on the goals of the founder, Tarsnap is more likely to outlive S3 than S3 Tarsnap.

But again: Primarily a hobby.

[1]: https://andrew-quinn.me/digital-resiliency-2025/

https://restic.readthedocs.io/en/stable/030_preparing_a_new_...

I would like to see an explicit discussion of what permissions are needed for what operation. I would also like to see a clearly specified model in which backups can be created in a bucket with less than full permissions and, even after active attack by an agent with those same permissions, one can enumerate all valid backups in the bucket and be guaranteed to be able to correctly restore any backup as long as one can figure out which backup one wants to restore.

Instead there are random guides on medium.com describing a configuration that may or may not have the desired effect.

will tell you the compressed size of your deduplicated data, which gives you the upload cost and first-month cost. 4GB of files usually works out to 3GB of dedup/compressed archive data for most people, less for people with many similar files.

$3000 per TB-year is accurate to my knowledge, and yes, it is at least one, and probably two, orders of magnitude what you can get with more general purpose systems. Backblaze B2 is $72 per TB-year; AWS Glacier is $12 per TB-year I believe; purchasing two 20 TB Seagate drives for $300 apiece, mirroring them, and replacing them every 3 years gives you about $10 per TB-year (potentially - most of us don't have 20 TB to back up in our personal lives). Those are the best prices I've been able to find with some looking [2].

To me, when I was building out the digital resiliency audit, the pricing and model just seemed to tell me that tarsnap was for very specific kinds of critical data backups, and was not a great fit for general purpose stuff. Like a lot of other people here I also have a general-purpose restic based 3-2-1 backup going for the ~150 GB in /home I back up. [3] My use of tarsnap is partly a cheap hedge for the handful of bytes of data I genuinely cannot afford to lose against issues with restic, Backblaze B2, systemd, etc.

[1]: https://hiandrewquinn.github.io/tarsnap-calculator/

[2]: https://andrew-quinn.me/digital-resiliency-2025/#postscript-...

[3]: https://andrew-quinn.me/digital-resiliency-2025/#general-bac...