From: Hugo Mills <hugo@carfax.org.uk>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Copy on write of unmodified data
Date: Wed, 25 May 2016 09:29:58 +0000 [thread overview]
Message-ID: <20160525092958.GH16712@carfax.org.uk> (raw)
In-Reply-To: <ae68a6ae-8184-88b8-05e5-8bb369d906b5@zytor.com>
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On Wed, May 25, 2016 at 01:58:15AM -0700, H. Peter Anvin wrote:
> Hi,
>
> I'm looking at using a btrfs with snapshots to implement a generational
> backup capacity. However, doing it the naïve way would have the side
> effect that for a file that has been partially modified, after
> snapshotting the file would be written with *mostly* the same data. How
> does btrfs' COW algorithm deal with that? If necessary I might want to
> write some smarter user space utilities for this.
Sounds like it might be a job for one of the dedup tools
(deupremove, bedup), or, if you're writing your own, the safe
deduplication ioctl which underlies those tools.
Hugo.
--
Hugo Mills | Well, sir, the floor is yours. But remember, the
hugo@... carfax.org.uk | roof is ours!
http://carfax.org.uk/ |
PGP: E2AB1DE4 | The Goons
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next prev parent reply other threads:[~2016-05-25 9:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-25 8:58 Copy on write of unmodified data H. Peter Anvin
2016-05-25 9:29 ` Hugo Mills [this message]
2016-05-25 11:00 ` H. Peter Anvin
2016-05-25 11:07 ` Hugo Mills
2016-05-25 11:32 ` Austin S. Hemmelgarn
2016-05-25 13:06 ` Dmitry Katsubo
2016-05-25 11:45 ` Austin S. Hemmelgarn
2016-05-25 12:28 ` Hugo Mills
2016-05-25 16:16 ` Henk Slager
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