Linux backup software .. that meets unique requirements

[tmetro-blu-5a1Jt6qxUNc at public.gmane.org (Tom Metro)]

David Rosenstrauch wrote:
> Ah, yes, I see you're right.  Just did some more reading, and experimenting.

Glad it makes sense now.


> So best solution looks like 2 rsync steps:  local src -> local 
> encrypted; local encrypted -> remote.
> 
> Pros:
> * backs up my files encrypted
> * (in theory) uses full rsync speed-ups
> * allows me to make full use of hard links (which the sshfs solution 
> didn't allow), which lets me store multiple generations of backups 
> efficiently
> 
> Cons:
> * In practice, rsync speed-ups are unlikely, since if a plaintext file 
> changes even 1 byte, its encrypted counterpart will likely look 
> radically different, and so rsync won't be able to back it up efficiently

I'm sounding like a broken record, but rsynccrypto was designed 
specifically to address the con you list. It uses rsync friendly 
compression and encryption. You're effectively trying to reinvent what 
it was designed to do, and your approach may be less optimal. (Though I 
don't know. I'd recommend benchmarking both. If you do, let us know how 
they compare.)

The wiki page you referenced implied that EncFS has a mode that is 
similarly rsync friendly.

(Keep in mind that any encryption scheme that is rsync friendly is 
inherently weaker than one that isn't, but the practical difference may 
be negligible for typical users. Same can be said for the compression.)


> Thanks again for the help thinking this through Tom!

You're welcome.

  -Tom

-- 
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/