Re: URGENT: Need help rebuilding iir RAID5 array with failed drive

Rainer Duffner wrote:
>
> Am 29.06.2008 um 05:11 schrieb Garrett Cooper:
>
>>
>> Just as you predicted, the disk(s) are unreadable still, even after
>> the rebuild (and I hope to hell that it didn't destroy/disturb any
>> data on the surviving members).
>>
>> I may just have to get it sent off for recovery (after I dd the
>> remaining members because there's still some usable data there --
>> bloody 2.7TB ... grr) -- apart from that I don't think I have a
>> choice.
>
>
> <tongue in cheek>
> If the data was worth so much that it values recovery....
> </tongue in cheek>
>
>>
>> Oh, where's this "document" of which you speak all the time? I don't
>> see anything about parity support not being available in either the
>> geom or iir manpage, or the iir sourcecode. If someone needs a helping
>> hand inserting that logic into the kernel, I'll gladly assist so
>> others don't follow my footsteps and fsck up their data.
>>
>
>
> On our HP DL320G5s, FreeBSD7 didn't even detect the MatrixRAID array 
> (RAID1).
> Even the Windoze-guys tell us that they don't trust it.
>
> So we settled for RAID1 via gmirror.
>
> MatrixRAID is a scam, if you ask me - like all the other BIOS-RAIDs we 
> have had the displeasure to see over the years.
> I really thought it was common knowledge.  But now that you mention 
> it, I can't find a reference to this in the FreeBSD docs (at least not 
> with a quick look).
> The handbook-example uses RAID1, though.
Perhaps a lesson as developers we should take from this, is to put a 
warning in ata about raid5. It's fooled Garret into believing he had a 
raid5, how many others are also using ata believing their raid5 is a 
raid5. We should warn people in the future rather than just saying 'its 
in the docs'. A kernel warning at attach is much more visible.

Cheers,
    Benjamin