From: Asdo <asdo@shiftmail.org>
To: Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>
Cc: linux-raid@vger.kernel.org
Subject: Re: Why does one get mismatches?
Date: Wed, 03 Mar 2010 00:27:25 +0100 [thread overview]
Message-ID: <4B8D9EDD.2080300@shiftmail.org> (raw)
In-Reply-To: <20100302185216.GB2243@lazy.lzy>
Piergiorgio Sartor wrote:
> Hi,
>
>> Now it would be interesting to understand why the mismatches don't
>> happen when LVM is above MD-raid!?
>>
>
> well, maybe LVM copies the buffer, and after it
> plays it nice with MD, i.e. no changes on the fly.
>
LVM copies the buffer!?
I don't think so...
LVM is near-zero overhead, so I would be surprised if it copied the buffer.
Also I don't think it was needed in their case, except maybe if there is
an I/O at the boundary of a logical volume or LVM stripe, which would
certainly be a mistake at requestor side.
LVM also does not merge requests AFAIR. (visible with mdstat -x 1)
> Or maybe, it is just one system that behaves
> properly with LVM over MD.
>
hmm maybe...
But me also I have never seen mismatches and the only raid-1's I have
are above LVM. (except /boot but that's almost never modified)
next prev parent reply other threads:[~2010-03-02 23:27 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-20 11:52 Fw: Why does one get mismatches? Jon Hardcastle
2010-01-22 18:13 ` Goswin von Brederlow
2010-01-24 17:40 ` Jon Hardcastle
2010-01-24 21:52 ` Roger Heflin
2010-01-24 23:13 ` Goswin von Brederlow
2010-01-25 10:07 ` Jon Hardcastle
2010-01-25 10:37 ` Goswin von Brederlow
2010-01-25 10:52 ` Jon Hardcastle
2010-01-25 17:32 ` Goswin von Brederlow
2010-01-25 19:32 ` Iustin Pop
2010-02-01 21:18 ` Bill Davidsen
2010-02-01 22:37 ` Neil Brown
2010-02-02 15:11 ` Bill Davidsen
2010-02-03 11:17 ` Goswin von Brederlow
2010-02-11 5:14 ` Neil Brown
2010-02-11 17:51 ` Bryan Mesich
2010-02-16 21:25 ` Bill Davidsen
2010-02-16 21:38 ` Steven Haigh
2010-02-17 3:19 ` Bryan Mesich
2010-02-17 23:05 ` Neil Brown
2010-02-19 15:18 ` Piergiorgio Sartor
2010-02-19 22:02 ` Neil Brown
2010-02-19 22:37 ` Piergiorgio Sartor
2010-02-19 23:34 ` Asdo
2010-02-20 4:27 ` Goswin von Brederlow
2010-02-20 11:12 ` Asdo
2010-02-21 11:13 ` Goswin von Brederlow
[not found] ` <8754A21825504719B463AD9809E54349@m5>
[not found] ` <20100221194400.GA2570@lazy.lzy>
2010-02-22 13:01 ` Asdo
2010-02-22 13:30 ` Piergiorgio Sartor
2010-02-22 13:44 ` Piergiorgio Sartor
2010-02-24 19:42 ` Bill Davidsen
2010-02-20 4:23 ` Goswin von Brederlow
2010-02-24 14:54 ` Bill Davidsen
2010-02-24 21:37 ` Neil Brown
2010-02-26 20:48 ` Bill Davidsen
2010-02-26 21:09 ` Neil Brown
2010-02-26 22:01 ` Piergiorgio Sartor
2010-02-26 22:15 ` Bill Davidsen
2010-02-26 22:21 ` Piergiorgio Sartor
2010-02-26 22:20 ` Asdo
2010-02-27 6:01 ` Michael Evans
2010-02-28 0:01 ` Bill Davidsen
2010-02-24 14:46 ` Bill Davidsen
2010-02-24 16:12 ` Martin K. Petersen
2010-02-24 18:51 ` Piergiorgio Sartor
2010-02-24 22:21 ` Neil Brown
2010-02-25 8:41 ` Piergiorgio Sartor
2010-03-02 4:57 ` Neil Brown
2010-03-02 18:49 ` Piergiorgio Sartor
2010-02-24 21:39 ` Neil Brown
[not found] ` <4B8640A2.4060307@shiftmail.org>
2010-02-25 10:41 ` Neil Brown
2010-02-28 8:09 ` Luca Berra
2010-03-02 5:01 ` Neil Brown
2010-03-02 7:36 ` Luca Berra
2010-03-02 10:04 ` Michael Evans
2010-03-02 11:02 ` Luca Berra
2010-03-02 12:13 ` Michael Evans
2010-03-02 18:14 ` Asdo
2010-03-02 18:52 ` Piergiorgio Sartor
2010-03-02 23:27 ` Asdo [this message]
2010-03-03 9:13 ` Piergiorgio Sartor
2010-03-03 11:42 ` Asdo
2010-03-03 12:03 ` Piergiorgio Sartor
2010-03-02 20:17 ` Neil Brown
2010-02-24 21:32 ` Neil Brown
2010-02-25 7:22 ` Goswin von Brederlow
2010-02-25 7:39 ` Neil Brown
2010-02-25 8:47 ` John Robinson
2010-02-25 9:07 ` Neil Brown
2010-02-11 18:12 ` Piergiorgio Sartor
-- strict thread matches above, loose matches on Subject: below --
2010-02-01 23:14 Jon Hardcastle
2010-01-25 20:43 greg
2010-01-25 22:49 ` Steven Haigh
2010-01-27 21:54 ` Tirumala Reddy Marri
2010-01-28 9:16 ` Jon Hardcastle
2010-01-28 10:29 ` Asdo
2010-01-28 17:20 ` Tirumala Reddy Marri
2010-01-28 18:23 ` Goswin von Brederlow
2010-01-28 19:03 ` Tirumala Reddy Marri
2010-01-28 20:24 ` Goswin von Brederlow
2010-01-29 15:37 ` Jon Hardcastle
2010-01-29 23:52 ` Goswin von Brederlow
2010-01-30 10:39 ` Jon Hardcastle
2010-02-01 21:10 ` Bill Davidsen
2010-01-20 15:03 Jon Hardcastle
2010-01-20 15:34 ` Brett Russ
2010-01-20 20:44 ` Majed B.
2010-01-20 22:25 ` Brett Russ
2010-01-20 22:30 ` Majed B.
2010-01-20 22:43 ` Brett Russ
2010-01-20 23:01 ` Christopher Chen
2010-01-21 4:17 ` Steven Haigh
2010-01-21 8:08 ` Asdo
2010-01-21 10:52 ` Steven Haigh
2010-01-21 11:48 ` Farkas Levente
2010-01-21 12:15 ` Jon Hardcastle
2010-01-19 10:04 Jon Hardcastle
2010-01-20 14:19 ` Brett Russ
2010-01-20 14:34 ` Jon Hardcastle
2010-01-20 14:46 ` Brett Russ
2010-02-01 20:48 ` Bill Davidsen
2010-01-22 16:22 ` Jon Hardcastle
2010-01-22 16:34 ` Asdo
2010-01-22 17:41 ` Brett Russ
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