Re: Read errors on raid5 ignored, array still clean .. then disaster !!

[Giovanni Tessore <giotex@texsoft.it>]

>>> Is this some kind of bug?  
>>>       
>> No
>>     
> I'm not sure I agree.
>   

Hm funny ... I just read now from md's man:

"In  kernels  prior to about 2.6.15, a read error would cause the same 
effect as a write error.  In later kernels, a read-error will instead 
cause md to attempt a recovery by overwriting the bad block. .... "

So things have changed since 2.6.15 ... I was not so wrong to expect 
"the old behaviour" and to be disappointed.
But something important was missing during this change imho:
1) let the old behaviour be the default: add 
/sys/block/mdXX/max_correctale_read_errors, with default to 0.
2) let the new behaviour be the default, but update mdadm and 
/proc/mdstat to report read error events.

I think the situation is now quite clear.
Thanks

-- 
Cordiali saluti.
Yours faithfully.

Giovanni Tessore