From: Christoph Hellwig <hch@infradead.org>
To: Ric Wheeler <rwheeler@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Michael Tokarev <mjt@tls.msk.ru>,
david@lang.hm, Pavel Machek <pavel@ucw.cz>,
Theodore Tso <tytso@mit.edu>, NeilBrown <neilb@suse.de>,
Rob Landley <rob@landley.net>, Florian Weimer <fweimer@bfk.de>,
Goswin von Brederlow <goswin-v-b@web.de>,
kernel list <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>,
mtk.manpages@gmail.com, rdunlap@xenotime.net,
linux-doc@vger.kernel.org, linux-ext4@vger.kernel.org,
corbet@lwn.net
Subject: Re: raid is dangerous but that's secret (was Re: [patch] ext2/3: document conditions when reliable operation is possible)
Date: Mon, 31 Aug 2009 09:16:26 -0400 [thread overview]
Message-ID: <20090831131626.GA17325@infradead.org> (raw)
In-Reply-To: <4A9BCCEF.7010402@redhat.com>
On Mon, Aug 31, 2009 at 09:15:27AM -0400, Ric Wheeler wrote:
>> While most common filesystem do have barrier support it is:
>>
>> - not actually enabled for the two most common filesystems
>> - the support for write barriers an cache flushing tends to be buggy
>> all over our software stack,
>>
>
> Or just missing - I think that MD5/6 simply drop the requests at present.
>
> I wonder if it would be worth having MD probe for write cache enabled &
> warn if barriers are not supported?
In my opinion even that is too weak. We know how to control the cache
settings on all common disks (that is scsi and ata), so we should always
disable the write cache unless we know that the whole stack (filesystem,
raid, volume managers) supports barriers. And even then we should make
sure the filesystems does actually use barriers everywhere that's needed
which failed at for years.
next prev parent reply other threads:[~2009-08-31 13:16 UTC|newest]
Thread overview: 309+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-12 9:21 ext2/3: document conditions when reliable operation is possible Pavel Machek
2009-03-12 11:40 ` Jochen Voß
2009-03-21 11:24 ` Pavel Machek
2009-03-21 11:24 ` Pavel Machek
2009-03-12 19:13 ` Rob Landley
2009-03-16 12:28 ` Pavel Machek
2009-03-16 19:26 ` Rob Landley
2009-03-23 10:45 ` Pavel Machek
2009-03-30 15:06 ` Goswin von Brederlow
2009-08-24 9:26 ` Pavel Machek
2009-08-24 9:31 ` [patch] " Pavel Machek
2009-08-24 11:19 ` Florian Weimer
2009-08-24 13:01 ` Theodore Tso
2009-08-24 14:55 ` Artem Bityutskiy
2009-08-24 22:30 ` Rob Landley
2009-08-24 19:52 ` Pavel Machek
2009-08-24 19:52 ` Pavel Machek
2009-08-24 20:24 ` Ric Wheeler
2009-08-24 20:52 ` Pavel Machek
2009-08-24 21:08 ` Ric Wheeler
2009-08-24 21:25 ` Pavel Machek
2009-08-24 22:05 ` Ric Wheeler
2009-08-24 22:22 ` Zan Lynx
2009-08-24 22:44 ` Pavel Machek
2009-08-25 0:34 ` Ric Wheeler
2009-08-24 23:42 ` david
2009-08-24 22:41 ` Pavel Machek
2009-08-24 22:39 ` Theodore Tso
2009-08-24 23:00 ` Pavel Machek
2009-08-25 0:02 ` david
2009-08-25 9:32 ` Pavel Machek
2009-08-25 0:06 ` Ric Wheeler
2009-08-25 9:34 ` Pavel Machek
2009-08-25 15:34 ` david
2009-08-26 3:32 ` Rik van Riel
2009-08-26 11:17 ` Pavel Machek
2009-08-26 11:29 ` david
2009-08-26 13:10 ` Pavel Machek
2009-08-26 13:43 ` david
2009-08-26 18:02 ` Theodore Tso
2009-08-27 6:28 ` Eric Sandeen
2009-08-27 6:28 ` Eric Sandeen
2009-11-09 8:53 ` periodic fsck was " Pavel Machek
2009-11-09 8:53 ` Pavel Machek
2009-11-09 14:05 ` Theodore Tso
2009-11-09 15:58 ` Andreas Dilger
2009-08-30 7:03 ` Pavel Machek
2009-08-26 12:28 ` Theodore Tso
2009-08-27 6:06 ` Rob Landley
2009-08-27 6:54 ` david
2009-08-27 7:34 ` Rob Landley
2009-08-28 14:37 ` david
2009-08-30 7:19 ` Pavel Machek
2009-08-30 12:48 ` david
2009-08-27 5:27 ` Rob Landley
2009-08-25 0:08 ` Theodore Tso
2009-08-25 9:42 ` Pavel Machek
2009-08-25 9:42 ` Pavel Machek
2009-08-25 13:37 ` Ric Wheeler
2009-08-25 13:42 ` Alan Cox
2009-08-27 3:16 ` Rob Landley
2009-08-25 21:15 ` Pavel Machek
2009-08-25 22:42 ` Ric Wheeler
2009-08-25 22:51 ` Pavel Machek
2009-08-25 23:03 ` david
2009-08-25 23:29 ` Pavel Machek
2009-08-25 23:03 ` Ric Wheeler
2009-08-25 23:26 ` Pavel Machek
2009-08-25 23:40 ` Ric Wheeler
2009-08-25 23:48 ` david
2009-08-25 23:53 ` Pavel Machek
2009-08-26 0:11 ` Ric Wheeler
2009-08-26 0:16 ` Pavel Machek
2009-08-26 0:31 ` Ric Wheeler
2009-08-26 1:00 ` Theodore Tso
2009-08-26 1:15 ` Ric Wheeler
2009-08-26 2:58 ` Theodore Tso
2009-08-26 10:39 ` Ric Wheeler
2009-08-26 10:39 ` Ric Wheeler
2009-08-26 11:12 ` Pavel Machek
2009-08-26 11:28 ` david
2009-08-29 9:49 ` [testcase] test your fs/storage stack (was Re: [patch] ext2/3: document conditions when reliable operation is possible) Pavel Machek
2009-08-29 11:28 ` Ric Wheeler
2009-09-02 20:12 ` Pavel Machek
2009-09-02 20:42 ` Ric Wheeler
2009-09-02 23:00 ` Rob Landley
2009-09-02 23:09 ` david
2009-09-03 8:55 ` Pavel Machek
2009-09-03 0:36 ` jim owens
2009-09-03 2:41 ` Rob Landley
2009-09-03 14:14 ` jim owens
2009-09-04 7:44 ` Rob Landley
2009-09-04 11:49 ` Ric Wheeler
2009-09-05 10:28 ` Pavel Machek
2009-09-05 12:20 ` Ric Wheeler
2009-09-05 13:54 ` Jonathan Corbet
2009-09-05 21:27 ` Pavel Machek
2009-09-05 21:56 ` Theodore Tso
2009-09-02 22:45 ` Rob Landley
2009-09-02 22:49 ` [PATCH] Update Documentation/md.txt to mention journaling won't help dirty+degraded case Rob Landley
2009-09-03 9:08 ` Pavel Machek
2009-09-03 12:05 ` Ric Wheeler
2009-09-03 12:31 ` Pavel Machek
2009-08-29 16:35 ` [testcase] test your fs/storage stack (was Re: [patch] ext2/3: document conditions when reliable operation is possible) david
2009-08-29 16:35 ` david
2009-08-30 7:07 ` Pavel Machek
2009-08-26 12:01 ` [patch] ext2/3: document conditions when reliable operation is possible Ric Wheeler
2009-08-26 12:23 ` Theodore Tso
2009-08-30 7:01 ` Pavel Machek
2009-08-30 7:01 ` Pavel Machek
2009-08-27 5:19 ` Rob Landley
2009-08-27 12:24 ` Theodore Tso
2009-08-27 13:10 ` Ric Wheeler
2009-08-27 13:10 ` Ric Wheeler
2009-08-27 16:54 ` MD/DM and barriers (was Re: [patch] ext2/3: document conditions when reliable operation is possible) Jeff Garzik
2009-08-27 18:09 ` Alasdair G Kergon
2009-09-01 14:01 ` Pavel Machek
2009-09-02 16:17 ` Michael Tokarev
2009-08-29 10:02 ` [patch] ext2/3: document conditions when reliable operation is possible Pavel Machek
2009-08-29 10:02 ` Pavel Machek
2009-08-26 1:15 ` Ric Wheeler
2009-08-26 1:16 ` Pavel Machek
2009-08-26 1:16 ` Pavel Machek
2009-08-26 2:55 ` Theodore Tso
2009-08-26 13:37 ` Ric Wheeler
2009-08-26 13:37 ` Ric Wheeler
2009-08-26 2:53 ` Henrique de Moraes Holschuh
2009-08-26 2:53 ` Henrique de Moraes Holschuh
2009-09-03 9:47 ` Pavel Machek
2009-09-03 9:47 ` Pavel Machek
2009-08-26 3:50 ` Rik van Riel
2009-08-27 3:53 ` Rob Landley
2009-08-27 11:43 ` Ric Wheeler
2009-08-27 20:51 ` Rob Landley
2009-08-27 22:00 ` Ric Wheeler
2009-08-28 14:49 ` david
2009-08-29 10:05 ` Pavel Machek
2009-08-29 20:22 ` Rob Landley
2009-08-29 21:34 ` Pavel Machek
2009-09-03 16:56 ` what fsck can (and can't) do was " david
2009-09-03 19:27 ` Theodore Tso
2009-08-27 22:13 ` raid is dangerous but that's secret (was Re: [patch] ext2/3: document conditions when reliable operation is possible) Pavel Machek
2009-08-28 1:32 ` Ric Wheeler
2009-08-28 6:44 ` Pavel Machek
2009-08-28 7:31 ` NeilBrown
2009-08-28 7:31 ` NeilBrown
2009-11-09 10:50 ` Pavel Machek
2009-08-28 11:16 ` Ric Wheeler
2009-09-01 13:58 ` Pavel Machek
2009-08-28 7:11 ` raid is dangerous but that's secret Florian Weimer
2009-08-28 7:23 ` NeilBrown
2009-08-28 12:08 ` raid is dangerous but that's secret (was Re: [patch] ext2/3: document conditions when reliable operation is possible) Theodore Tso
2009-08-30 7:51 ` Pavel Machek
2009-08-30 9:01 ` Christian Kujau
2009-09-02 20:55 ` Pavel Machek
2009-08-30 12:55 ` david
2009-08-30 14:12 ` Ric Wheeler
2009-08-30 14:44 ` Michael Tokarev
2009-08-30 16:10 ` Ric Wheeler
2009-08-30 16:35 ` Christoph Hellwig
2009-08-31 13:15 ` Ric Wheeler
2009-08-31 13:16 ` Christoph Hellwig [this message]
2009-08-31 13:19 ` Mark Lord
2009-08-31 13:21 ` Christoph Hellwig
2009-08-31 15:14 ` jim owens
2009-09-03 1:59 ` Ric Wheeler
2009-09-03 11:12 ` Krzysztof Halasa
2009-09-03 11:18 ` Ric Wheeler
2009-09-03 13:34 ` Krzysztof Halasa
2009-09-03 13:50 ` Ric Wheeler
2009-09-03 13:59 ` Krzysztof Halasa
2009-09-03 14:15 ` wishful thinking about atomic, multi-sector or full MD stripe width, writes in storage Ric Wheeler
2009-09-03 14:26 ` Florian Weimer
2009-09-03 15:09 ` Ric Wheeler
2009-09-03 23:50 ` Krzysztof Halasa
2009-09-04 0:39 ` Ric Wheeler
2009-09-04 21:21 ` Mark Lord
2009-09-04 21:29 ` Ric Wheeler
2009-09-05 12:57 ` Mark Lord
2009-09-05 13:40 ` Ric Wheeler
2009-09-05 21:43 ` NeilBrown
2009-09-07 11:45 ` Pavel Machek
2009-09-07 13:10 ` Theodore Tso
2010-04-04 13:47 ` fsck more often when powerfail is detected (was Re: wishful thinking about atomic, multi-sector or full MD stripe width, writes in storage) Pavel Machek
2010-04-04 13:47 ` Pavel Machek
2010-04-04 17:39 ` tytso
2010-04-04 17:59 ` Rob Landley
2010-04-04 18:45 ` Pavel Machek
2010-04-04 19:35 ` tytso
2010-04-04 19:29 ` tytso
2010-04-04 23:58 ` Rob Landley
2009-09-03 14:35 ` raid is dangerous but that's secret (was Re: [patch] ext2/3: document conditions when reliable operation is possible) david
2009-08-31 13:22 ` Ric Wheeler
2009-08-31 15:50 ` david
2009-08-31 16:21 ` Ric Wheeler
2009-08-31 18:31 ` Christoph Hellwig
2009-08-31 19:11 ` david
2009-08-30 15:05 ` Pavel Machek
2009-08-30 15:20 ` Theodore Tso
2009-08-31 17:49 ` Jesse Brandeburg
2009-08-31 18:01 ` Ric Wheeler
2009-08-31 21:01 ` MD5/6? (was Re: raid is dangerous but that's secret ...) Ron Johnson
2009-08-31 18:07 ` raid is dangerous but that's secret (was Re: [patch] ext2/3: document conditions when reliable operation is possible) martin f krafft
2009-08-31 22:26 ` Jesse Brandeburg
2009-08-31 22:26 ` Jesse Brandeburg
2009-08-31 23:19 ` Ron Johnson
2009-09-01 5:45 ` martin f krafft
2009-08-31 17:49 ` Jesse Brandeburg
2009-09-05 10:34 ` Pavel Machek
2009-09-05 10:34 ` Pavel Machek
2009-08-30 7:51 ` Pavel Machek
2009-08-25 23:46 ` [patch] ext2/3: document conditions when reliable operation is possible david
2009-08-25 23:08 ` Neil Brown
2009-08-25 23:44 ` Pavel Machek
2009-08-26 4:08 ` Rik van Riel
2009-08-26 11:15 ` Pavel Machek
2009-08-27 3:29 ` Rik van Riel
2009-08-25 16:11 ` Theodore Tso
2009-08-25 22:21 ` [patch] document flash/RAID dangers Pavel Machek
2009-08-25 22:21 ` Pavel Machek
2009-08-25 22:33 ` david
2009-08-25 22:40 ` Pavel Machek
2009-08-25 22:59 ` david
2009-08-25 23:37 ` Pavel Machek
2009-08-25 23:48 ` Ric Wheeler
2009-08-26 0:06 ` Pavel Machek
2009-08-26 0:12 ` Ric Wheeler
2009-08-26 0:20 ` Pavel Machek
2009-08-26 0:26 ` david
2009-08-26 0:28 ` Ric Wheeler
2009-08-26 0:38 ` Pavel Machek
2009-08-26 0:45 ` Ric Wheeler
2009-08-26 11:21 ` Pavel Machek
2009-08-26 11:58 ` Ric Wheeler
2009-08-26 12:40 ` Theodore Tso
2009-08-26 13:11 ` Ric Wheeler
2009-08-26 13:11 ` Ric Wheeler
2009-08-26 13:44 ` david
2009-08-26 13:40 ` Chris Adams
2009-08-26 13:47 ` Alan Cox
2009-08-26 14:11 ` Chris Adams
2009-08-27 21:50 ` Pavel Machek
2009-08-29 9:38 ` Pavel Machek
2009-08-26 4:24 ` Rik van Riel
2009-08-26 11:22 ` Pavel Machek
2009-08-26 14:45 ` Rik van Riel
2009-08-29 9:39 ` Pavel Machek
2009-08-29 11:47 ` Ron Johnson
2009-08-29 16:12 ` jim owens
2009-08-25 23:56 ` david
2009-08-26 0:12 ` Pavel Machek
2009-08-26 0:20 ` david
2009-08-26 0:39 ` Pavel Machek
2009-08-26 1:17 ` david
2009-08-26 0:26 ` Ric Wheeler
2009-08-26 0:44 ` Pavel Machek
2009-08-26 0:50 ` Ric Wheeler
2009-08-26 1:19 ` david
2009-08-26 11:25 ` Pavel Machek
2009-08-26 12:37 ` Theodore Tso
2009-08-30 6:49 ` Pavel Machek
2009-08-30 6:49 ` Pavel Machek
2009-08-26 4:20 ` Rik van Riel
2009-08-25 22:27 ` [patch] document that ext2 can't handle barriers Pavel Machek
2009-08-25 22:27 ` Pavel Machek
2009-08-27 3:34 ` [patch] ext2/3: document conditions when reliable operation is possible Rob Landley
2009-08-27 8:46 ` David Woodhouse
2009-08-28 14:46 ` david
2009-08-29 10:09 ` Pavel Machek
2009-08-29 16:27 ` david
2009-08-29 21:33 ` Pavel Machek
2009-08-24 23:00 ` Pavel Machek
2009-08-25 13:57 ` Chris Adams
2009-08-25 22:58 ` Neil Brown
2009-08-25 23:10 ` Ric Wheeler
2009-08-25 23:32 ` NeilBrown
2009-08-25 23:32 ` NeilBrown
2009-08-24 21:11 ` Greg Freemyer
2009-08-24 21:11 ` Greg Freemyer
2009-08-25 20:56 ` Rob Landley
2009-08-25 21:08 ` david
2009-08-25 18:52 ` Rob Landley
2009-08-25 14:43 ` Florian Weimer
2009-08-24 13:50 ` Theodore Tso
2009-08-24 18:48 ` Pavel Machek
2009-08-24 18:48 ` Pavel Machek
2009-08-24 18:39 ` Pavel Machek
2009-08-24 13:21 ` Greg Freemyer
2009-08-24 13:21 ` Greg Freemyer
2009-08-24 18:44 ` Pavel Machek
2009-08-25 23:28 ` Neil Brown
2009-08-25 23:28 ` Neil Brown
2009-08-26 1:34 ` david
2009-08-24 21:11 ` Rob Landley
2009-08-24 21:33 ` Pavel Machek
2009-08-25 18:45 ` Jan Kara
2009-03-16 12:30 ` Pavel Machek
2009-03-16 19:03 ` Theodore Tso
2009-03-23 18:23 ` Pavel Machek
2009-03-23 18:23 ` Pavel Machek
2009-03-16 19:40 ` Sitsofe Wheeler
2009-03-16 21:43 ` Rob Landley
2009-03-17 4:55 ` Kyle Moffett
2009-03-23 11:00 ` Pavel Machek
2009-08-29 1:33 ` Robert Hancock
2009-08-29 13:04 ` Alan Cox
2009-03-16 19:45 ` Greg Freemyer
2009-03-16 19:45 ` Greg Freemyer
2009-03-16 21:48 ` Pavel Machek
[not found] <dddMw-7Xt-57@gated-at.bofh.it>
[not found] ` <dddWc-83W-51@gated-at.bofh.it>
[not found] ` <ddefx-5R-37@gated-at.bofh.it>
[not found] ` <ddep7-bI-7@gated-at.bofh.it>
[not found] ` <ddeyR-iy-11@gated-at.bofh.it>
[not found] ` <ddeyR-iy-9@gated-at.bofh.it>
[not found] ` <ddeIu-n9-9@gated-at.bofh.it>
[not found] ` <ddeSb-th-29@gated-at.bofh.it>
[not found] ` <ddoRI-11a-39@gated-at.bofh.it>
[not found] <ciPTu-7f2-47@gated-at.bofh.it>
[not found] ` <clrhX-3R1-13@gated-at.bofh.it>
[not found] ` <dcEc1-33Z-17@gated-at.bofh.it>
[not found] ` <dcFUz-4yN-9@gated-at.bofh.it>
[not found] ` <dcHtf-5XC-17@gated-at.bofh.it>
[not found] ` <dcNSc-2DU-11@gated-at.bofh.it>
[not found] ` <dcOl9-3aC-19@gated-at.bofh.it>
[not found] ` <dcOOd-3qM-33@gated-at.bofh.it>
[not found] ` <dcOXN-3M5-15@gated-at.bofh.it>
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