Tarsnap – Online backups for the truly paranoid (tarsnap.com)

(https://news.ycombinator.com/user?id=cperciva)

Tip: forget everything you knew about scheduling full and incremental backups, because you don't have to. Tarsnap provides logical snapshots and does all the diff magic for you.

(Hence tar ... snap)

Now, of course, if you are truly paranoid, you'll want to review their code first. I don't get why I can't simply mount a volume with encription and write there. Using code that is already on my machine (on the kernel, nonetheless) would make it a much simpler decision.

    Storage:	300 picodollars / byte-month
    ($0.30 / GB-month)
    Bandwidth:	300 picodollars / byte
    ($0.30 / GB)

More generally, I've always found it to be a good idea to be at least somewhat circumspect if you're going to have some kind of an asocial relationship with somebody (e.g., getting them to give you money). It's impossible to foretell what people will get annoyed by, so you might as well give them as few things to get annoyed by as possible. (I suppose this is the "better to keep quiet and be thought a fool..." principle, in a way, though obviously foolishness is not the precise issue here. Oh well. I don't claim to be original.)

If prices were listed in dollars per GB instead of picodollars per byte, it would be harder to avoid the what-is-a-GB confusion (a GB is 10^9 bytes, but some people don't understand SI prefixes). Picodollars are perfectly clear — nobody is going to think that a picodollar is 2^(-40) dollars.

Specifying prices in picodollars reinforces the point that if you have very small backups, you can pay very small amounts. Unlike some people, I don't believe in rounding up to $0.01 — the Tarsnap accounting code keeps track of everything in attodollars and when it internally converts storage prices from picodollars per month to attodollars per day it rounds the prices down.

Plus, as others have pointed out, prices are listed in standard units (dollars per GB) just below the oddball ones.

But also, you picked out only one of the three reasons he listed (http://www.tarsnap.com/picoUSD-why.html); the other two are also important:

If prices were listed in dollars per GB instead of picodollars per byte, it would be harder to avoid the what-is-a-GB confusion (a GB is 10^9 bytes, but some people don't understand SI prefixes). Picodollars are perfectly clear — nobody is going to think that a picodollar is 2^(-40) dollars.

Specifying prices in picodollars reinforces the point that if you have very small backups, you can pay very small amounts. Unlike some people, I don't believe in rounding up to $0.01 — the Tarsnap accounting code keeps track of everything in attodollars and when it internally converts storage prices from picodollars per month to attodollars per day it rounds the prices down.

And finally, the price in dollars per GB are also prominently displayed, right after the price in picodollars per byte. So really, you're just being bothered that he's having a little bit of geeky fun even though it has absolutely no effect on you.

If you're paranoid about it being closed source, you can make a quick script to encrypt sensitive data, copy it to another folder, then sync that encrypted folder online. I do something similar with a small % of my data.

As far as server backups, it's trivial to script a copy to your local machine then let Crashplan sync that.

Glad to see you on the front page.

http://www.haystacksoftware.com/arq/

You're using the --snaptime option, right? It's necessary when you're backing up a filesystem snapshot in order to work around a race condition with them -- if a file is modified, the filesystem snapshot is created, and then the file is modified again, all within a single time quantum, it can trick Tarsnap into thinking that the file hasn't been modified later (which triggers an optimization of "this must be the same blocks as it was last time" in place of the usual "read the file and split it into blocks" behaviour).

Finally, compression and deduplication is amazing:

Well, if we're going to be posting statistics here...

                                         Total size  Compressed size
  All archives                               269 TB           121 TB
    (unique data)                            177 GB            72 GB

The bar you're setting, though, is impossibly high. Can you absolutely, positively, definitely trust that your machine is not rooted and some nefarious entity isn't quietly collecting your every keystroke and snickering in the dark while stroking a white cat?

At that level of paranoia, you're probably best off using a device personally soldered together with hand-selected transistors that XORs all your backups with the white noise collected from your tv (while disconnected from cable, of course).

This situation has never arisen, but if I'm confronted by a police officer and enough evidence that I'm sure they could get a court order, I'd rather be cooperative than force them to go through the courts. This doesn't mean that I'd give them any more data than they would get from a court order -- in fact, quite the opposite, since police tend to err on the side of requesting more than they need when going through the courts, and cooperating could change "seize a server" into "get a copy of the required data".

Seriously though, it is on my list of issues which needs to be addressed. Bringing in someone else and getting them up to speed on how to run everything is an expensive prospect, though.

It's a decent tool. I encrypt with a separate gpg key, do mostly incremental backups, and a full one every few months. Incremental backups take under a minute on my desktop (100K files, 11G). Full ones are kind of slow (which is why I set it to only do it every few months).

I haven't used the S3 support.

Paranoia means encrypting everything which might be sensitive, even if you can't see any way for it to be abused.