OS X backups?

[Finn Hughes]

Hi,

I was looking at using rsync with the --extented-attributes option to preserver ACLs and resource forks. I believe this is what will allow me to backup OS X thinks like the iPhoto library successfully.

However since myself and my girlfriend share a lot of content, multi-user block based deduplication is very interesting and hence I've come across backshift :)

Do you know if backshift can backup OS X ACLs and resource forks, is it likely to work or be easy to add?

If you can't see any showstoppers I'll try and find the time and energy to have a play sometime in the next month or so.

Thanks,
Finn

[Dan Stromberg]

Backshift does not currently back up any extended attributes.

It's unlikely to be easy to add (it'd probably require a ctypes-based module), but if you come up with patches that pass pylint, I'd be happy to merge them.

--
Dan Stromberg

[Finn Hughes]

Thanks for the speedy response,

A bit more involved than I was hoping then, I've got a passing familiarity with ctypes, and while it makes Python look ugly, it's not too bad ;)

I've had a quick google and found this rsync patch
http://quesera.com/reynhout/misc/rsync+hfsmode/

It looks involved enough that if I did have a look I would be largely reusing his GPL code and even then it looks a little problematic, he's suggesting mechanisms to force checksumming of the ACLs and resource forks as modification time and size are not reliable indicators of if the file has changed... needs more thought when I'm less tired.

Finn

[Dan Stromberg]

Backshift re-saves all metadata it knows about on every backup, so there's no need to diff metadata. Hopefully that'll keep things a little simpler.

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Dan Stromberg