[clug] Cloud + rsync + backup

Andrew Janke a.janke at gmail.com
Mon Aug 3 02:13:32 UTC 2015

On 3 August 2015 at 12:05, Eyal Lebedinsky <eyal at eyal.emu.id.au> wrote:
> Could you simply keep an encrypted filesystem in the cloud? This runs the risk
> of the encryption key being there too. Not good.
> So the traffic should be already encrypted. I would consider keeping a local
> backup, in the format you want to sync out (encrypted). Keep the local
> up-to-date with something smart (roll your own?) and rsync the local backup
> to the cloud. Small cleartext changes will still export a large amount of data.
> This needs more thinking but I will be surprised if there is not already a
> good solution - this is a common problem.

Indeed. Your thoughts above mirror mine. Some talk about local caches
of metadata to checksums but then roll their own diff things. I'd
prefer to stick with tried and true things like rsync where possible.
And thus your suggestion of a local copy is what I've been
investigating. The idea being an encrypted squashfs mount on loop that
I write to using dirvish and then somehow diff the image to send only
diff data. But ideally I'd prefer to keep the current and diffs to
previous versions. Not quite sure how I achieved the second part. This
is more about ease or recovery and trying to avoid the need to send a
complete image every now and then.

Perhaps btrfs or zfs can offer some magick via snapshots.  Or even
squashfs does diffs and I've just not looked hard enough.


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