Permissions causing full backups?

Link McGinnis link2 at cschristian.com
Thu Apr 27 21:50:40 GMT 2006


>=20
> On Thu, 2006-04-27 at 14:21 -0400, Link McGinnis wrote:
> > I am using rsync/rsnapshot on Windows XP (via cygwin) to backup to a
> > mapped share (/u) on a Linux server.
>=20
> > .f...p... /cygdrive/c/Documen=85.
> > snapshot_root    /cygdrive/u/docs_bkup/
> > rsync_short_args           -arltgoDvzi
> >
> You mean you have mounted a share from some Linux server as U: on your
> Windows machine and rsnapshot is transferring from C: to U:, both =
drives
> accessed through Cygwin?  This arrangement strikes me as very awkward.
> For one thing, you don't get the benefit of incremental transfer. =20

Hmm! It didn't seem that obvious to me.  Thanks for clarifying!

> I can see how permissions on U: would get mangled in rsync to Cygwin =
to
> Windows to Samba (I'm guessing) to Linux conversion, causing U: to
> ignore rsync's attempt to set the permissions from the source on it.
> That means the permissions differ every time, so rsync doesn't try to
> hard link files, but even if it did, hard linking is unlikely to work
> through layers of Cygwin, Windows, and Samba.
>=20
> As a workaround, don't preserve permissions.  You clearly tried to
> preserve everything except permissions, but keep in mind that -a, your
> first short option, includes -p.  Delete the a: "-rltgoDvzi".  I would
> also recommend not preserving user and group ownership.  This should =
get
> rid of the itemized differences, but rsync is still likely to fail to
> hard link identical files.

I tested with "-rltgoDvzi" and it did NOT attempt to backup any files =
AND it
DID fail to hard link files.  Great insight. =20
=20
> A better solution would be to have the Windows machine push the files =
to
> an rsync daemon running on the Linux server. =20

Am I still using cygwin for this or how do I "push"?  I should mention =
that
I hope to backup several PC's to their users' area of the samba machine.
Will this solution allow for that?

> However, rsnapshot only
> supports local snapshot roots, so you would have write your own script
> to invoke rsync.  This isn't so bad. =20

Easy for you to say...

> Just come up with a name for the destination directory=20

Can you elaborate on "come up with a name for..."

> and use --link-dest to link to the previous one.
> To set up an rsync daemon, write a configuration file according to the
> instructions in rsyncd.conf(5), and then invoke the daemon using rsync
> --daemon --config=3D<the-file>.  This strategy will give you =
incremental
> transfer and hard linking, and you can safely tell rsync to preserve
> permissions.  Nonetheless, the permissions rsync reads through Cygwin
> won't meaningfully represent Windows permissions.

BTW1, I have to say that I've read a lot of "expert" replies on forums =
and
I've never seen anyone who has carefully read the question and replied =
with
so much detail and precision as you.  Thank you!

BTW2, I'm not sure that I've replied correctly to this list.  Let me =
know if
I should be using another method.

Thanks again,

Link McGinnis

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