From: Hugo Mills <hugo@carfax.org.uk>
To: Duncan <1i5t5.duncan@cox.net>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: stability matrix (was: Is stability a joke?)
Date: Tue, 20 Sep 2016 08:19:28 +0000 [thread overview]
Message-ID: <20160920081928.GP7138@carfax.org.uk> (raw)
In-Reply-To: <pan$9faa9$336f6d31$1fa59209$17e07862@cox.net>
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On Tue, Sep 20, 2016 at 07:59:44AM +0000, Duncan wrote:
> Christoph Anton Mitterer posted on Mon, 19 Sep 2016 21:45:46 +0200 as
> excerpted:
>
> > On Mon, 2016-09-19 at 17:27 +0200, David Sterba wrote:
> >
> >> > For specific features:
> >> > - Autodefrag
> >> > - didn't that also cause reflinks to be broken up?
> >>
> >> No and never had.
> >
> > Absolutely sure? One year ago, I was told that at first too so I started
> > using it, but later on some (IIRC) developer said auto-defrag would also
> > suffer from it.
>
> AFAIK it was Hugo that said he looked into that, and that (if I'm
> representing it correctly) autodefrag breaks reflinks and triggers space-
> using duplication much as defrag does, but that it does it on a much
> smaller scale, since it (1) only triggers when some parts of a file are
> being rewritten anyway, thus breaking the reflink for those specific
> parts of the file due to COW (COW1 on otherwise NOCOW files) in any case,
> and (2) unlike defrag, doesn't rewrite and thus break the reflinks on
> entire files, just somewhat larger extents than the pure rewrite by
> itself without autodefrag would.
>
> Thus making the reflink-breaking and duplication effect of autodefrag
> there, but relatively quite small compared to on-demand per-file defrag.
I didn't investigate it -- It was my firmly-stated misunderstanding
which caused someone (Filipe, I think) with much more actual knowledge
to correct me, thus making the actual behaviour much clearer. :)
I think your description is accurate as far as my current
understanding goes.
Hugo.
> --
> Duncan - List replies preferred. No HTML msgs.
> "Every nonfree program has a lord, a master --
> and if you use the program, he is your master." Richard Stallman
>
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--
Hugo Mills | There isn't a noun that can't be verbed.
hugo@... carfax.org.uk |
http://carfax.org.uk/ |
PGP: E2AB1DE4 |
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next prev parent reply other threads:[~2016-09-20 8:19 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-11 8:55 Is stability a joke? Waxhead
2016-09-11 9:56 ` Steven Haigh
2016-09-11 10:23 ` Martin Steigerwald
2016-09-11 11:21 ` Zoiled
2016-09-11 11:43 ` Martin Steigerwald
2016-09-11 12:05 ` Martin Steigerwald
2016-09-11 12:39 ` Waxhead
2016-09-11 13:02 ` Hugo Mills
2016-09-11 14:59 ` Martin Steigerwald
2016-09-11 20:14 ` Chris Murphy
2016-09-12 12:20 ` Austin S. Hemmelgarn
2016-09-12 12:59 ` Michel Bouissou
2016-09-12 13:14 ` Austin S. Hemmelgarn
2016-09-12 14:04 ` Lionel Bouton
2016-09-15 1:05 ` Nicholas D Steeves
2016-09-15 8:02 ` Martin Steigerwald
2016-09-16 7:13 ` Helmut Eller
2016-09-15 5:55 ` Kai Krakow
2016-09-15 8:05 ` Martin Steigerwald
2016-09-11 14:54 ` Martin Steigerwald
2016-09-11 15:19 ` Martin Steigerwald
2016-09-11 20:21 ` Chris Murphy
2016-09-11 17:46 ` Marc MERLIN
2016-09-20 16:33 ` Chris Murphy
2016-09-11 17:11 ` Duncan
2016-09-12 12:26 ` Austin S. Hemmelgarn
2016-09-11 12:30 ` Waxhead
2016-09-11 14:36 ` Martin Steigerwald
2016-09-12 12:48 ` Swâmi Petaramesh
2016-09-12 13:53 ` Chris Mason
2016-09-12 17:36 ` Zoiled
2016-09-12 17:44 ` Waxhead
2016-09-15 1:12 ` Nicholas D Steeves
2016-09-12 14:27 ` David Sterba
2016-09-12 14:54 ` Austin S. Hemmelgarn
2016-09-12 16:51 ` David Sterba
2016-09-12 17:31 ` Austin S. Hemmelgarn
2016-09-15 1:07 ` Nicholas D Steeves
2016-09-15 1:13 ` Steven Haigh
2016-09-15 2:14 ` stability matrix (was: Is stability a joke?) Christoph Anton Mitterer
2016-09-15 9:49 ` stability matrix Hans van Kranenburg
2016-09-15 11:54 ` Austin S. Hemmelgarn
2016-09-15 14:15 ` Chris Murphy
2016-09-15 14:56 ` Martin Steigerwald
2016-09-19 14:38 ` David Sterba
2016-09-19 15:27 ` stability matrix (was: Is stability a joke?) David Sterba
2016-09-19 17:18 ` stability matrix Austin S. Hemmelgarn
2016-09-19 19:52 ` Christoph Anton Mitterer
2016-09-19 20:07 ` Chris Mason
2016-09-19 20:36 ` Christoph Anton Mitterer
2016-09-19 21:03 ` Chris Mason
2016-09-19 19:45 ` stability matrix (was: Is stability a joke?) Christoph Anton Mitterer
2016-09-20 7:59 ` Duncan
2016-09-20 8:19 ` Hugo Mills [this message]
2016-09-20 8:34 ` David Sterba
2016-09-19 15:38 ` Is stability a joke? David Sterba
2016-09-19 21:25 ` Hans van Kranenburg
2016-09-12 16:27 ` Is stability a joke? (wiki updated) David Sterba
2016-09-12 16:56 ` Austin S. Hemmelgarn
2016-09-12 17:29 ` Filipe Manana
2016-09-12 17:42 ` Austin S. Hemmelgarn
2016-09-12 20:08 ` Chris Murphy
2016-09-13 11:35 ` Austin S. Hemmelgarn
2016-09-15 18:01 ` Chris Murphy
2016-09-15 18:20 ` Austin S. Hemmelgarn
2016-09-15 19:02 ` Chris Murphy
2016-09-15 20:16 ` Hugo Mills
2016-09-15 20:26 ` Chris Murphy
2016-09-16 12:00 ` Austin S. Hemmelgarn
2016-09-19 2:57 ` Zygo Blaxell
2016-09-19 12:37 ` Austin S. Hemmelgarn
2016-09-19 4:08 ` Zygo Blaxell
2016-09-19 15:27 ` Sean Greenslade
2016-09-19 17:38 ` Austin S. Hemmelgarn
2016-09-19 18:27 ` Chris Murphy
2016-09-19 18:34 ` Austin S. Hemmelgarn
2016-09-19 20:15 ` Zygo Blaxell
2016-09-20 12:09 ` Austin S. Hemmelgarn
2016-09-15 21:23 ` Christoph Anton Mitterer
2016-09-16 12:13 ` Austin S. Hemmelgarn
2016-09-19 3:47 ` Zygo Blaxell
2016-09-19 12:32 ` Austin S. Hemmelgarn
2016-09-19 15:33 ` Zygo Blaxell
2016-09-12 19:57 ` Martin Steigerwald
2016-09-12 20:21 ` Pasi Kärkkäinen
2016-09-12 20:35 ` Martin Steigerwald
2016-09-12 20:44 ` Chris Murphy
2016-09-13 11:28 ` Austin S. Hemmelgarn
2016-09-13 11:39 ` Martin Steigerwald
2016-09-14 5:53 ` Marc Haber
2016-09-12 20:48 ` Waxhead
2016-09-13 8:38 ` Timofey Titovets
2016-09-13 11:26 ` Austin S. Hemmelgarn
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