Tarsnap is amazing for Unix systems. Flat out, one of the coolest services I've ever used, and one of the cheapest. I'm backing up my VPS with it, and I can't recommend it enough.
I have a friend that strongly recommends CrashPlan, but I haven't tried it out yet on my Mac. I'm curious to though.
I use CrashPlan both on Mac and on Windows. On the Mac it works very well. On Windows it is okay, though it needs some hand holding -- sometimes the service gets stuck and needs to be restarted manually. Overall I find that it is better than Mozy (a competing service).
I love Crashplan -- especially because with essentially the same client, you can do backups to a public service, a hosted business service (multiple machines, centrally managed keys, etc.) or an enterprise hosted-by-yourself service.
Doesn't Tarsnap store your data on their S3 account, rather than your own? If so, if how do you get your data back from Amazon if Tarsnap vanished tomorrow?
Tarsnap isn't going to vanish tomorrow. It's steadily profitable so I don't need to worry about "runway".
Even if I get hit by lightning tomorrow, the service runs perfectly fine on its own for months at a time, so you'd have plenty of time to get your data back.
How would people know if anything had happened to you and that they should begin to recover data - is there a dead man switch or notification procedure in place?
Thanks for the feedback -- yes, this is something I plan on doing (amidst all the other tasks I'm juggling...).
I very commonly hear why people are using Tarsnap, and from time to time I hear why people are no longer using Tarsnap, but I very rarely hear why people never started using Tarsnap, so I really appreciate you taking the time to comment.
You can say that about any service--what if Crashplan's data center caught fire tomorrow? Tarsnap might be run by a single guy (I think?) but saying S3 is "more" or "less" reliable than any other private company isn't a great comparison. In any case a massive company like Amazon is the most likely to be reliable in these cases, I imagine.
My earlier point was that I think data is stored on Colin Percival's S3 account (he is the creator of Tarsnap) and therefore you might lose access to the data (if he couldn't pay the bills or got hit by a bus) even though S3 itself is fine.
I use Arq to backup files on my MacBook - it saves them to my S3 bucket, so even if everyone working on Arq dies (I sincerely hope they don't!) and their servers all explode, my backups are still intact on S3 - which is less likely to go down permanently and lose all my files than Tarsnap (not that that is particularly likely either!).
There are definitely tiers of reliability. An external drive drive is easily lost or damaged. A backup service can take individual drive/server losses but that might be the limit. S3 can lose an entire data center - the only real risk comes from software bugs.
This isn't really a concern for me, but I'd probably email Colin and ask for it. The tarsnap program is open-source, presumably if he stopped hosting it the server-side component could be replaced. The client does all the work.
I have a friend that strongly recommends CrashPlan, but I haven't tried it out yet on my Mac. I'm curious to though.