target that injects errors?

target that injects errors?

[Zach Brown]

I find myself wanting to test a patch that reacts to EIO deep in aio
O_DIRECT.  Has anyone done a target that can inject errors into the IO
path?  I found sct's "testdrive", but it seems a bit crufty these days:

  http://people.redhat.com/sct/patches/testdrive/

If someone hasn't done this, I'll take a swing at it.

Thanks.

- z

Re: target that injects errors?

[Alasdair G Kergon]

On Mon, Mar 13, 2006 at 06:53:06PM -0800, Zach Brown wrote:
> Has anyone done a target that can inject errors into the IO
> path?
 
A couple so far:
  dm-flakey - injects errors
  dm-rwsplit - sends reads and writes to different paths
               which could be given different characteristics
               before getting recombined.

http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/dm-flakey.patch
http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/dm-rwsplit.patch

(I'd like to see dm-flakey enhanced.)

Alasdair
-- 
agk@redhat.com

Re: target that injects errors?

[Zach Brown]

> A couple so far:
>   dm-flakey - injects errors
>   dm-rwsplit - sends reads and writes to different paths
>                which could be given different characteristics
>                before getting recombined.

Excellent, thanks, I'll give these a try.

- z

how to trace the device mapper?

[Jui-Pin Yang]

Hi,
I would like to trace the device mapper, and any good suggestion to do the
job
is welcome such as how to start and so on.
Thanks

Best Regards

Jui-Pin Yang
=====================================
Network & Communication Technology Center
Computer & Communications Research Laboratory
Industrial Technology Research Institute

P300 CCL/ITRI
No.31, Gongye 2nd Rd., Annan District
Tainan City 709, Taiwan (R.O.C.)
Tel: 886-6-3847103
Fax: 886-6-3847182
E-mail: jpyang@itri.org.tw
=====================================

Re: how to trace the device mapper?

[Alan D. Brunelle]

Jui-Pin Yang wrote:

>Hi,
>I would like to trace the device mapper, and any good suggestion to do the
>job
>is welcome such as how to start and so on.
>Thanks
>  
>
If you are looking for interactions with the underlying block I/O layer 
interfaces, you could look into blktrace.

Alan D. Brunelle
HP

>Best Regards
>
>Jui-Pin Yang
>=====================================
>Network & Communication Technology Center
>Computer & Communications Research Laboratory
>Industrial Technology Research Institute
>
>P300 CCL/ITRI
>No.31, Gongye 2nd Rd., Annan District
>Tainan City 709, Taiwan (R.O.C.)
>Tel: 886-6-3847103
>Fax: 886-6-3847182
>E-mail: jpyang@itri.org.tw
>=====================================
>
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>  
>