From: NeilBrown <neilb@suse.de>
To: jakub@gooseman.cz
Cc: Mikael Abrahamsson <swmike@swm.pp.se>, linux-raid@vger.kernel.org
Subject: Re: bug: 4-disk md raid10 far2 can be assembled clean with only two disks, causing silent data corruption
Date: Tue, 25 Sep 2012 22:32:27 +1000 [thread overview]
Message-ID: <20120925223227.130ef8e3@notabene.brown> (raw)
In-Reply-To: <152edbf7bdad33717477f174f94116b7@192.168.93.35>
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On Tue, 25 Sep 2012 11:48:34 +0200 <jakub@gooseman.cz> wrote:
>
> On Tue, 25 Sep 2012 07:00:44 +0200 (CEST), Mikael Abrahamsson
> <swmike@swm.pp.se> wrote:
> > On Tue, 25 Sep 2012, NeilBrown wrote:
> >
> >> Why do you say that "the write IO errors are invisible for the
> >> filesystem"? They are certainly reported in the kernel logs that you
> >> should and I'm sure an application would see them if it checked return
> >> status properly.
> >>
> >> md is behaving as designed here. It deliberately does not fail the
> >> whole array, it just fails those blocks which are no longer accessible.
> >
>
> Would you please refer to some documentation that this behaviour is
> correct? I now tried to fail several disks in raid5, raid0 and raid10-near,
> in case of r0 and r10n, mdadm didn't even allow me to remove more disks
> than is sufficient to access all the data. In case of r5 I was able to fail
> 2 out of 3, but the array was correctly marked as FAILED and couldn't be
> accessed at all. I'd expect that behaviour even in my case of raid10-far. I
> can't even assmenble and run it with less than required count of disks.
>
Could you please be explicit about exactly how the behaviour that you think
of as "correct" would differ from the current behaviour? Because I cannot
really see what point you are making - I need a little help.
Thanks,
NeilBrown
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next prev parent reply other threads:[~2012-09-25 12:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-24 13:37 bug: 4-disk md raid10 far2 can be assembled clean with only two disks, causing silent data corruption Jakub Husák
2012-09-25 4:19 ` NeilBrown
2012-09-25 5:00 ` Mikael Abrahamsson
2012-09-25 9:48 ` jakub
2012-09-25 11:14 ` keld
2012-09-25 11:47 ` John Robinson
2012-09-25 12:32 ` NeilBrown [this message]
[not found] ` <50628B39.90205@gooseman.cz>
2012-09-26 5:41 ` NeilBrown
2012-09-26 8:28 ` keld
2012-09-26 8:59 ` John Robinson
2012-09-26 9:08 ` keld
2012-09-26 9:23 ` keld
[not found] ` <5067F014.5020600@gooseman.cz>
2012-09-30 10:24 ` keld
[not found] <50601CED.1050607@gooseman.cz>
2012-09-24 8:46 ` bug: 4-disk md raid10 far2 can be assembled clean with only two disks, causing "silent" " Jakub Husák
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