[dm-devel] Re: ATARAID/FakeRAID/HPTRAID/PDCRAID as dm targets?

[Jeff Garzik]

Carl-Daniel Hailfinger wrote:
> Wilfried Weissmann wrote:
> 
>>Arjan van de Ven wrote:
>>
>>
>>>On Sat, Mar 20, 2004 at 07:23:01PM -0700, Kevin P. Fleming wrote:
>>>
>>>
>>>>Jeff Garzik wrote:
>>>>
>>>>
>>>>
>>>>>So go ahead, and I'll lend you as much help as I can.  I have the
>>>>>full Promise RAID docs, and it seems like another guy on the lists
>>>>>has full Silicon Image "medley" RAID docs...
> 
> 
> Jeff: May I request your docs?

Unfortunately not, but I can get you in touch with somebody at Promise 
who can.  They're definitely interested in working with the open source 
community.  Not public...


> Well, I had something in mind which closely resembles the ataraid-detect
> tool Thomas Horsten (Medley RAID) suggested.
> 
> http://lists.infowares.com/archive/medley/2004-February/000001.html
> 
> OK, I was even aiming for less: Write an ataraid-detect tool which outputs
> the correct mapping for dmsetup. If I manage to write it generically
> enough, it can be integrated into evms or used as a standalone program,
> whatever you like.

That's pretty nice.  Very Unix-ish:  provide a small, pluggable piece 
that does one thing, and does it well.


>>1. its all within evms
>>There is no need for additional tools required to setup the volume
>>(thinking about installers and initrd...).
> 
> 
> The EVMS sample initrd is HUGE. (2.1 MB) I'm aiming for a initrd size of
> less than 1/10 of that.

Cool :)


>>4. nice clickety-click user interface
>>Especially useful for lazy people like me. ;)
> 
> 
> I prefer the "no user interface" approach. But then again, I'm biased.

Agreed -- a minimal implementation is needed first anyway.  The BIOS of 
these proprietary RAID thingies typically provides the user interface.


>>What do you think?
> 
> 
> I'll use your work as a foundation. First step is integrating detection
> for non-HPT arrays. If the code looks too messy after that, I still can
> refactor it.
> 
> As soon as I have some code to get at least PDCRAID working, I'll post again.

Feel free to ask me questions, too.

	Jeff