
Online backups for the truly paranoid - nodivbyzero
http://www.tarsnap.com/
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rubinlinux
For my nearly 1TB backup size, this would cost per month the same as my
Crashplan account costs per year. Why are all these linux friendly backup
services (this, rsync.net etc) so much more expensive?

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cperciva
Two reasons come to mind:

1\. Tarsnap isn't VC-backed, so it can't play the "sell dollar bills for 80
cents each" game to expand its customer base. (On the flip side, this means
that you don't have to worry about Tarsnap shutting down if it can't get any
more VC money.)

2\. "Consumer grade" backup services save a lot of money thanks to the fact
that their customers skew heavily towards using only a small fraction of the
storage space they are paying for. I think that approach to pricing is
borderline dishonest; with Tarsnap you'll pay for exactly what you use (which
means that a lot of people are paying a few cents per month).

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cperciva
I think most people here are already well aware of Tarsnap... but I'm always
happy to answer questions.

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Cogito
For what it's worth:

\- I'm sure there are new people who have never heard of it before, I used to
be one of them and your presence made it _much_ more visible (that and
everyone talking about how they trusted you to do crypto...)

\- I don't keep track of what's going on with tarsnap, so whenever it hits the
front page I make sure to have a read and see if there is any new information

So no question, just a thank you and a reminder to myself to set up my
backups.

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lwhalen
How is this different from using Duplicity with a PGP key and throwing it to
S3/B2?

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cperciva
That's a bit vague, but some of the more substantial differences are:

1\. Duplicity works with a "full plus increments" model, whereas Tarsnap's
archives are deduplicated snapshots. If you've been doing daily backups for a
year, getting your data back using Duplicity means downloading a full backup
followed by 365 increments; to get your data back using Tarsnap you directly
download whichever archive you want.

2\. Related to the above, Tarsnap's snapshot model allows you to delete
archives independently; with Duplicity, you can't delete an archive if you
want to keep increments which depend on it.

3\. Tarsnap has built-in support for restricted keys; this allows you to set
up a server which can create new archives but can't read or delete them. (With
a bit of effort you can create "user" keys in AWS which can do S3 PUTs but not
GETs or DELETEs; but if your server is compromised that wouldn't stop someone
from overwriting your backups.)

4\. Duplicity uses librsync, which is considerably more memory-hungry. It's
possible that they worked around this by limiting its matching-block search to
individual files -- I haven't looked at their code -- but that would result in
it failing to recognize moved or copied files.

5\. I haven't run benchmarks, but algorithmically speaking Tarsnap should be
significantly faster at creating archives.

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lwhalen
Thank you for the detailed reply!

