From: Chris Mason <chris.mason@oracle.com>
To: Lubos Kolouch <lubos.kolouch@gmail.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Copy/move btrfs volume
Date: Thu, 1 Jul 2010 21:29:33 -0400 [thread overview]
Message-ID: <20100702012933.GB15319@think> (raw)
In-Reply-To: <i0huf7$98a$1@dough.gmane.org>
On Thu, Jul 01, 2010 at 11:33:59AM +0000, Lubos Kolouch wrote:
> Daniel J Blueman, Thu, 01 Jul 2010 12:26:10 +0100:
> >> What is the correct way to do this?
> >
> > The only way to do this preserving duplication is to use hardlinks
> > between duplicated files (which reference counts the inode), and use
> > 'rsync -H'.
> >
> > Dan
>
> But when the files are on different snaphots, does rsync see them as
> hardlinked?
>
> A scenario - I have raid5 of say, 1TB HDDs. It contains many snapshots.
> Then, few years later, new machine is bought and there are, say, 5TB
> discs.
>
> So I need to transfer the btrfs volume to the new machine.
>
> But how to do it so that it looks the *same*, ie. the same snapshots?
> I could of course write a custom script to create the subvolume, rsync
> the files, create snapshot, rsync files, etc,
>
> but it would be nice if the btrfs toolset supports this by default...
This is definitely something I'm looking to add. The btrfs-progs git
tree has some code that allows userland to walk the btrees and detect
the duplicate files. But this is just a building block needed for the
full backup program.
Instead of hard links, it is possible to use reflinks with cp, which
uses the cloning ioctl.
-chris
prev parent reply other threads:[~2010-07-02 1:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-01 10:28 Copy/move btrfs volume Lubos Kolouch
2010-07-01 11:26 ` Daniel J Blueman
2010-07-01 11:33 ` Lubos Kolouch
2010-07-01 22:21 ` Matt Brown
2010-07-02 6:15 ` Oystein Viggen
2010-07-03 7:33 ` Lubos Kolouch
2010-07-21 15:00 ` Hubert Kario
2010-07-02 1:29 ` Chris Mason [this message]
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