Re: [Gelato-technical] Serious performance degradation on a RAID

[Andreas Hirstius <Andreas.Hirstius@cern.ch>]

David Mosberger wrote:

>>>>>>On Wed, 06 Apr 2005 10:33:07 +0200, Andreas Hirstius <Andreas.Hirstius@cern.ch> said:
>>>>>>            
>>>>>>
>
>  Andreas> But the driver in questions is 3w-9xxx and there have been
>  Andreas> no chances at all in this driver between 2.6.10 and
>  Andreas> 2.6.12-rc1. The changed driver in -rc2 still has the
>  Andreas> problem.  And I've tried the driver built-in and as a
>  Andreas> module (default)...
>
>Are you sure the problem is due to the driver and not RAID0?  What if
>you dd directly from the underlying device?
>
>  
>
To make sure it's not the md/raid I just took the driver/md directory 
from 2.6.9 and 2.6.10 and used it in 2.6.11 => no change in behaviour ...
(The changes in md.c are minor and there are no changes in raid0.c 
between .10 and .11 anyway)

As I say on the webpage, a dd on the underlying devices works fine...

It might still be a higher level interface to the md, that's wrong.

And I'm not saying that it's the 3w-9xx driver!! It hasn't changed 
between 2.6.10 and 2.6.11, so pretty much impossible to introduce bugs 
there...
(It was just mentioned wrt to the fusion-mpt driver.)

Andreas

>	--david
>
>  
>