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From: Neil Brown <neilb@cse.unsw.edu.au>
To: scott-kernel@thomasons.org
Date: Wed, 12 Mar 2003 14:37:29 +1100
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Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: bio too big device
In-Reply-To: message from scott thomason on Tuesday March 11
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On Tuesday March 11, scott-kernel@thomasons.org wrote:
> I frequently receive this message in my syslog, apparently 
> whenever there are periods of significant write activity:
> 
>     bio too big device ide0(3,7) (256 > 255)
>     bio too big device ide1(22,6) (256 > 255)
> 
> It's worth noting that on this system I have had ongoing trouble 
> with system stability during write activity as well, using a 
> wide variety of 2.5.x kernels, even though at the time of this 
> symptom things are apparently running fine.
> 
> Filesystems are all ext3 on top soft raid0 devices. This happens 
> to be 2.5.64, but it has been happening for at least the last 
> 5-6 versions.
> 
> Ideas? Any further debugging output I can provide?


raid0 doesn't really work well in 2.5 yet.... as you have noticed.

We really need to grab the bio splitting code out of md/dm.c and use
it to split bios that are too big or that cross device boundaries.

any volunteers??

NeilBrown