I've been using Tarsnap for almost a decade for a small, but very important, personal data subset.
Tarsnap is very resilient; it doesn't do a lot, but what it does is solid. The mailing list is helpful, and you can reach out to its creators directly for prompt, useful responses if that is something you don't want on the mailing list (where names and email addresses are in the clear; use marc.info to search in it).
But if you are trying to start with Tarsnap, you should note a few things from the beginning:
- If you are looking for a completely (or even almost) frictionless backup experience - this is not it. Also, it doesn't have tons of features - which might be a good thing, but you should know and accept it.
- If you're used to tools like Backblaze, CrashPlan, Restic, or Borg, the limited feature set might frustrate you.
- Knowing this in advance will help you set expectations within its feature set. The doc/man pages are great resources once you actually read it.
- It has some quirks (may or may not be bugs) that require tinkering with your settings, env etc. Getting your hands dirty with sample data first is a great way to know Tarsnap.
- Set up your logs and scripts such that you can know/debug things later.
- Naming of your archives is important.
- You'll need at least two keys: a master key with read, write, and delete access on your archives/Tarnsap storage, and a un-passphrased regular key with only "write" permission for backups. Keep both safe, especially the master key. There's "nuke" as well…
- I used its GUI for the longest time but would absolutely not recommend it. It hides a lot, which might come back to bite you, and is not the most polished tool of all. Its last release was 7 years ago.
OP says:
> … If you use it solely to back up the few megabytes of “crown jewels” data we all have lying around"
and I actually use Tarsnap exclusively for my "crown jewels," which are in the early three digit MBs.
- So, unlike what many say, I do believe it is costly for today's storage/bw prices, especially if your data isn't very compressible. Tarsnap's compression is great, but not magic. However, i doesn't cost an exponential bomb either. Killer de-dupe though.
- You must have a plan for what and how much you want to back up, and the expected growth of that data.
- It is definitely not a "fire and forget" tool (and you should never forget your backups anyway).
I was frustrated with it until I gave up on the GUI, embraced the CLI/cron, reduced the amount of data being backed up and excluded (using copy and delete) some data being stored, and accepted what it can't do. Which is not really great but that's what it is.
Glaring omissions, IMHO: very few maintenance features (the scripts listed are not easy to work with), (almost?) no way of knowing what file changed in a certain archive, slow restores (may matter for a bigger data set), and the lack of an updated, polished GUI tool which I think is very important for personal data backup.
My request to cperciva would be: please consider this - while it's inspired by tar and stays close to it, it's also a cloud backup tool. Treating it a bit more like a modern cloud backup tool could be useful. Just my two cents.