Re: [rdiff-backup-users] FreeBSD and xattr OS X support

[Andrew Ferguson]

Will Prater wrote:
> Hello,
> 
> Im trying to get Resource for support on FreeBSD 6.1.  Here is the  
> output from rdiff-backup:
> 
> ====================
> address@hidden /usr/ports/sysutils/rdiff-backup]# rdiff-backup -v5 -- 
> print-statistics /host/cobalt/c/fun/ /backup/cobalt/funUnable to  
> import module xattr.
> Extended attributes not supported on filesystem at /host/cobalt/c/fun
> ACLs not supported by filesystem at /host/cobalt/c/fun
> -----------------------------------------------------------------
> Detected abilities for source (read only) file system:
>    Access control lists                         Off
>    Extended attributes                          Off
>    Case sensitivity                             On
>    Mac OS X style resource forks                Off
>    Mac OS X Finder information                  Off
> -----------------------------------------------------------------
> <snip>
> ======================
> 
> How does one get the "Mac OS X style resource forks" and "Mac OS X  
> Finder information" options enabled?  Is this something to do with  
> pyxattr?  I could not seem to get that module to install on FreeBSD.

All five of these things refer to different properties *of the
filesystem* that have or have not been detected.

Only the Mac filesystem HFS+ supports "Mac OS X style resource forks"
and "Mac OS X Finder information". Unless you have some bizarre setup,
you shouldn't expect to see that as 'On' for a Free BSD box. If your
FreeBSD box *does* use HFS+ as a filesystem, you'll have to use a python
distribution where the usually Mac-only calls are enabled for your OS.

Extended attributes are file attributes at the filesystem level. I know
ext3fs has them (but you need to explicitly turn them on as a mount
option) and the Mac HFS+ filesystem has them. The python module pyxattr
(http://pyxattr.sourceforge.net/) supports them for ext2/ext3 or XFS on
Linux and the python module xattr (http://undefined.org/python/)
supports them for HFS+ on Mac OS X.

So, if you're running FreeBSD, I don't think either of these options are
for you, but sufficient Googling could certainly prove me wrong.

ACL's are a whole different beast (although on an implementation level,
they could be stored in the extended attributes). There's a pylibacl
module (http://pylibacl.sourceforge.net/), which supports Linux and
makes a strange claim about FreeBSD support. For Mac OS X, ACL support
will require it's own python module.

One last note: if the system you are backing up from supports feature X
and the destination system does not support feature X, rdiff-backup will
store the properties of feature X in it's metadata file and restore the
metadata on the backed-up system upon file restore. This is what makes
rdiff-backup perfect for backing-up, say, Mac OS X machines to Linux
servers.

Best,
Andrew


-- 
Andrew Ferguson - address@hidden