From: Ric Wheeler <ric@emc.com>
To: Tomasz Torcz <zdzichu@irc.pl>
Cc: Thomas Glanzmann <sithglan@stud.uni-erlangen.de>,
"Theodore Ts'o" <tytso@mit.edu>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: ext4 features
Date: Thu, 06 Jul 2006 11:12:47 -0400 [thread overview]
Message-ID: <44AD286F.3030507@emc.com> (raw)
In-Reply-To: <20060701181702.GC8763@irc.pl>
Tomasz Torcz wrote:
>On Sat, Jul 01, 2006 at 07:47:16PM +0200, Thomas Glanzmann wrote:
>
>
>>Hello,
>>
>>
>>>Checksums are not very useful for themselves. They are useful when we
>>>have other copy of data (think raid mirroring) so data can be
>>>reconstructed from working copy.
>>>
>>>
>>it would be possible to identify data corruption.
>>
>>
>
> Yes, but what good is identification? We could only return I/O error.
>Ability to fix corruption (like ZFS) is the real killer.
>
>
Having a checksum (or even a digital signature on a file) that lets us
detect corruption is very useful since, in many cases, it allows us to
flag the file as corrupt before it gets used.
In some cases, this is a big hint that you should restore it from backup
(tape, other disk, etc).
I think that it is a generally useful thing even when not on a self
correcting device,
ric
next prev parent reply other threads:[~2006-07-06 15:19 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-01 16:33 ext4 features Thomas Glanzmann
2006-07-01 17:07 ` Tomasz Torcz
2006-07-01 17:47 ` Thomas Glanzmann
2006-07-01 18:09 ` Claudio Martins
2006-07-01 18:59 ` Thomas Glanzmann
2006-07-01 18:17 ` Tomasz Torcz
2006-07-03 9:44 ` Gabor Gombas
2006-07-03 20:22 ` Helge Hafting
2006-07-03 20:55 ` Tomasz Torcz
2006-07-03 21:01 ` Arjan van de Ven
2006-07-03 21:46 ` Jeff V. Merkey
2006-07-03 21:25 ` Diego Calleja
2006-07-03 22:17 ` Alan Cox
2006-07-04 14:45 ` Jan Engelhardt
2006-07-04 16:35 ` Jeffrey V. Merkey
2006-07-04 18:52 ` Jeff Garzik
2006-07-04 19:40 ` Jeffrey V. Merkey
2006-07-05 13:35 ` Lew Palm
2006-07-03 23:01 ` Jeff V. Merkey
2006-07-04 9:14 ` Benny Amorsen
2006-07-05 4:21 ` Bill Davidsen
2006-07-05 5:13 ` H. Peter Anvin
2006-07-05 5:45 ` Jeffrey V. Merkey
2006-07-07 14:12 ` Pavel Machek
2006-07-05 10:38 ` Krzysztof Halasa
2006-07-07 14:10 ` Pavel Machek
2006-07-07 17:45 ` Krzysztof Halasa
2006-07-07 21:30 ` Pavel Machek
2006-07-08 10:52 ` Krzysztof Halasa
2006-07-08 10:55 ` Pavel Machek
2006-07-08 11:19 ` Krzysztof Halasa
2006-07-08 11:23 ` Pavel Machek
2006-07-08 18:45 ` Avi Kivity
2006-07-08 20:24 ` Krzysztof Halasa
2006-07-04 9:22 ` Petr Tesarik
2006-07-04 11:35 ` Peter Zijlstra
2006-07-04 11:55 ` ext4 features (salvage) Petr Tesarik
[not found] ` <80294dc60607040508l1022d164ybe0ba10858e54f0c@mail.gmail.com>
2006-07-04 12:31 ` Petr Tesarik
2006-07-04 12:42 ` Helge Hafting
2006-07-04 16:20 ` Matthew Frost
2006-07-04 15:25 ` ext4 features Pavel Machek
2006-07-05 4:10 ` Bill Davidsen
2006-07-03 21:46 ` Valdis.Kletnieks
[not found] ` <Pine.LNX.4.61.0607032354170.31747@yvahk01.tjqt.qr>
2006-07-04 14:37 ` Kernel recycler [was: ext4 features] Jan Engelhardt
2006-07-04 11:14 ` ext4 features Krzysztof Halasa
2006-07-04 22:35 ` Frank van Maarseveen
2006-07-04 23:47 ` Claudio Martins
2006-07-03 22:12 ` Alan Cox
2006-07-03 21:59 ` Arjan van de Ven
2006-07-03 23:31 ` ext4 features (checksums) Neil Brown
2006-07-04 1:03 ` Jeff Garzik
2006-07-04 6:09 ` Avi Kivity
2006-07-04 7:02 ` Neil Brown
2006-07-04 8:26 ` Avi Kivity
2006-07-05 11:56 ` Bill Davidsen
2006-07-05 12:06 ` Bill Davidsen
2006-07-05 12:19 ` Avi Kivity
2006-07-08 17:54 ` Bill Davidsen
2006-07-04 8:17 ` Alan Cox
2006-07-04 11:08 ` Thomas Glanzmann
2006-07-04 11:19 ` Krzysztof Halasa
2006-07-04 12:49 ` Helge Hafting
2006-07-05 12:01 ` Bill Davidsen
2006-07-05 12:10 ` Avi Kivity
2006-07-08 18:02 ` Bill Davidsen
2006-07-06 0:36 ` Blatant layering violations (was Re: ext4 features) Valerie Henson
2006-07-06 12:15 ` Xavier Bestel
2006-07-06 17:06 ` Valdis.Kletnieks
2006-07-06 20:02 ` Tom Vier
2006-07-03 21:34 ` ext4 features Bill Davidsen
2006-07-03 21:50 ` Valdis.Kletnieks
2006-07-03 22:04 ` Bruce Ferrell
2006-07-04 14:48 ` Valdis.Kletnieks
2006-07-03 23:00 ` Bill Davidsen
2006-07-04 15:01 ` Valdis.Kletnieks
2006-07-05 2:40 ` Bill Davidsen
2006-07-05 2:47 ` Valdis.Kletnieks
2006-07-04 12:52 ` Helge Hafting
2006-07-06 15:12 ` Ric Wheeler [this message]
2006-07-06 17:05 ` Krzysztof Halasa
2006-07-06 17:27 ` Ric Wheeler
2006-07-06 20:52 ` Valdis.Kletnieks
2006-07-07 17:41 ` Krzysztof Halasa
2006-07-07 17:34 ` Krzysztof Halasa
2006-07-04 1:02 ` Theodore Tso
2006-07-04 19:16 ` Thomas Glanzmann
2006-07-04 19:30 ` Valdis.Kletnieks
2006-07-05 12:24 ` Bill Davidsen
2006-07-05 12:59 ` J. Bruce Fields
2006-07-05 13:17 ` Pádraig Brady
2006-07-05 19:33 ` Trond Myklebust
2006-07-05 21:22 ` Bill Davidsen
2006-07-05 21:42 ` Trond Myklebust
2006-07-08 21:04 ` Bill Davidsen
2006-07-10 20:08 ` Trond Myklebust
2006-07-10 22:37 ` Bill Davidsen
2006-07-11 2:36 ` Trond Myklebust
2006-07-21 3:10 ` Bill Davidsen
2006-07-21 12:06 ` Trond Myklebust
2006-07-21 14:36 ` Theodore Tso
2006-07-21 19:02 ` Trond Myklebust
2006-07-22 12:25 ` Theodore Tso
2006-07-05 21:12 ` Bill Davidsen
2006-07-05 21:27 ` linux-os (Dick Johnson)
2006-07-05 21:41 ` J. Bruce Fields
2006-07-06 2:32 ` Bill Davidsen
2006-07-06 2:42 ` Nigel Cunningham
2006-07-06 12:43 ` Trond Myklebust
2006-07-07 2:15 ` Bill Davidsen
2006-07-07 2:30 ` Trond Myklebust
2006-07-07 2:42 ` Ric Wheeler
2006-07-07 2:46 ` Trond Myklebust
2006-07-07 3:16 ` Bill Davidsen
2006-07-07 8:09 ` Bernd Petrovitsch
2006-07-07 14:56 ` Trond Myklebust
2006-07-07 19:52 ` Theodore Tso
2006-07-05 14:04 ` Avi Kivity
2006-07-04 14:36 ` Andi Kleen
2006-07-04 14:43 ` Thomas Glanzmann
[not found] <6tVcC-1e1-79@gated-at.bofh.it>
[not found] ` <6tVcC-1e1-81@gated-at.bofh.it>
[not found] ` <6tVcC-1e1-83@gated-at.bofh.it>
[not found] ` <6tWib-2Ly-7@gated-at.bofh.it>
[not found] ` <6uDdv-7bs-3@gated-at.bofh.it>
[not found] ` <6uDGF-7Nj-47@gated-at.bofh.it>
[not found] ` <6uDQb-8e8-9@gated-at.bofh.it>
[not found] ` <6uDQb-8e8-13@gated-at.bofh.it>
[not found] ` <6uE9y-d1-1@gated-at.bofh.it>
[not found] ` <6uPom-87W-23@gated-at.bofh.it>
2006-07-04 12:28 ` Bodo Eggert
2006-07-04 15:32 ` Valdis.Kletnieks
[not found] ` <6uEMp-1gr-41@gated-at.bofh.it>
[not found] ` <6uUo2-6SN-5@gated-at.bofh.it>
[not found] ` <6uW6v-15i-19@gated-at.bofh.it>
[not found] ` <6vfLY-4K5-33@gated-at.bofh.it>
2006-07-05 22:40 ` Bodo Eggert
[not found] ` <6uXYv-3RG-1@gated-at.bofh.it>
[not found] ` <6veG8-350-7@gated-at.bofh.it>
[not found] ` <6vfiU-465-13@gated-at.bofh.it>
[not found] ` <6vmNk-77r-23@gated-at.bofh.it>
[not found] ` <6vnq7-7Tw-55@gated-at.bofh.it>
[not found] ` <6vrN0-5Se-9@gated-at.bofh.it>
[not found] ` <6vBsY-38p-9@gated-at.bofh.it>
2006-07-07 9:38 ` Bodo Eggert
2006-07-07 14:37 ` Trond Myklebust
2006-07-09 9:50 ` Bodo Eggert
-- strict thread matches above, loose matches on Subject: below --
2006-07-08 2:22 Chuck Ebbert
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