Backup Central

getting oriented questions
**dual 2.5 PM G5 running Tiger (10.4.2)**

I'm just getting into rdiff-backup so if these questions are to simple
please just point me in the right direction :-)

I'm working on an ongoing (wip) article <a
href="http://homepage.mac.com/lee_cullens/Bx3.html">Backup::Restore</a>
that includes native tool usage examples. I was just getting into some
of the more "elaborate" uses of Tiger's new rsync (which isn't quite
ready for prime time yet) and in looking around for various uses came
across rdiff-backup. I think including a good open source tool would be
appropriate and took the easy out of installing it from DarwinPorts
which included the dependency librsync.

I also dabble a little in Python and have Bob's 2.4.1 pythonmac installed.

So with that understood, I am interested in ACL and EA support.

First, for EA support I have installed "xattr" (pythonmac package) which
is to Mac OS X what pyxattr is to Linux (though I don't think the
implementations are quite compatible). Will rdiff-backup recognize
"xattr" and preserve user-level Extended Attributes?

Second, for ACL support I don't seem to have anything called "pylibacl"
on my system and can't find it in the Mac specific packages. Is this
Mac compatible and if so where might be the best place to find it (for
someone not accustomed to building things on Mac and Unix)?

Thank you,
Lee C

Ok, lets take a different shot at this :-)

I would like to checkout rdiff-backup usage on Mac OS X (10.4.2)

1) Are there any other such users out there?

2) I want to use the full functionality but there are two limitations,
namely ACLs and EAs. The various port packages have "librsync" included
as a dependency but do not include pylibacl and pyxattr.

2a) EA support: supposedly with "pyxattr" recognized, but in Mac OS
X the proper module is "xattr" which I have in my pythonmac 2.4.1
installation (/usr/local/) and in the DarwinPorts environment
(/opt/local/). Other than my PATH variable, how do I get
rdiff-backup to recognize "xattr?"

2b) ACL support: supposedly with "pylibacl" recognized, but I can't
find any such thing for Darwin. The "standard" download setup.py
checks for Linux and Free-BSD only and quits. Having looked (with
my limited understanding) at the Carbon "FPGetACL" which pylibacl
would, I believe, have to get down to, I'm not adventurous enough to
just add Darwin to the setup.py. Is there any merit in pursuing
this aspect?


Thank you,
Lee C

Ben Escoto wrote:

Chinook <chinook.nr < at > tds.net>
wrote the following on Sat, 17 Sep 2005 23:38:49 -0400





I would like to checkout rdiff-backup usage on Mac OS X (10.4.2)

1) Are there any other such users out there?



Well not me but I think there are some :)



2) I want to use the full functionality but there are two limitations,
namely ACLs and EAs. The various port packages have "librsync" included
as a dependency but do not include pylibacl and pyxattr.

2a) EA support: supposedly with "pyxattr" recognized, but in Mac OS
X the proper module is "xattr" which I have in my pythonmac 2.4.1
installation (/usr/local/) and in the DarwinPorts environment
(/opt/local/). Other than my PATH variable, how do I get
rdiff-backup to recognize "xattr?"

2b) ACL support: supposedly with "pylibacl" recognized, but I can't
find any such thing for Darwin. The "standard" download setup.py
checks for Linux and Free-BSD only and quits. Having looked (with
my limited understanding) at the Carbon "FPGetACL" which pylibacl
would, I believe, have to get down to, I'm not adventurous enough to
just add Darwin to the setup.py. Is there any merit in pursuing
this aspect?



For EAs, rdiff-backup looks for the "xattr" module, as provided by the
pyxattr package. For ACL support, rdiff-backup looks for the
"posix1e" package, as provided by the pylibacl package. There are
links to these packages on the homepage.

I have no idea whether Mac OS X supports ACLs or user EAs at all, and
if it does, whether the pyxattr and pylibacl packages are Mac OS X
compatible. If you have questions specifically about these modules
though, you may want to ask the modules' author or mailing list.




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Thanks for the reply Ben,

As per 2a above, it's a matter of the rdiff -backup "import" statement
that is in question - guess I'll have to dig through the source to check
it out.

As for 2b above, your reply did prompt me to look back at the pylibacl
page again and this time I noticed what may be the closest thing to an
answer I'll get

It says (circa 2002):
"If any other platform implements the POSIX.1e draft, pylibacl can be
used."
And the Darwin (OS X) man pages say:
"This implementation of the POSIX.1e library differs from the standard in
a number of non-portable ways in order to support the MacOS/Darwin ACL
semantic. Where possible, these differences are implemented using the
mechanisms provided in the standard for such extensions. Where
routines
are non-standard, they are suffixed with _np to indicate that they are
not portable."

In trying all the potential info sources I could, I have so far found
one user of rdiff-backup on the pythonmac list and that person is still
running Panther (10.3.x). EAs were implemented in Darwin with Tiger
(10.4.x).

You saw the post so maybe some other Mac users will eventually also
All a bit of a shame in my mind - with all the playing around with
rsync I've done, rdiff-backup seems a very practical and efficient
approach.

Thanks again for the reply,
Lee C