Status of Tripe Parity RAID

Status of Tripe Parity RAID

[Ronny Egner]

Dear All,

i would like to ask about the status of Tripe Parity RAID.

I´ve found some posts on the list from Andrea Mazzoleni dating back to
2013 
but after that nothing seemed to be moving.

If this is currently not on the wish list i would like to add that as
Feature Request :-)


Thanks Neil for this great piece of software.


Mit freundlichen Grüßen
Ronny Egner
--
Ronny Egner
Oracle Certified Master 11g (OCM)
 
EMail:      ronnyegner@ronnyegner-consulting.de
<mailto:roonnyegner@ronnyegner-consulting.de>

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Re: Status of Tripe Parity RAID

[NeilBrown]

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On Sat, 2 Aug 2014 08:11:31 +0000 Ronny Egner
<ronnyegner@ronnyegner-consulting.de> wrote:

> Dear All,
> 
> i would like to ask about the status of Tripe Parity RAID.
> 
> I´ve found some posts on the list from Andrea Mazzoleni dating back to
> 2013 
> but after that nothing seemed to be moving.
> 
> If this is currently not on the wish list i would like to add that as
> Feature Request :-)

If you want wishes fulfilled, you'll need to find a genie.

> 
> 
> Thanks Neil for this great piece of software.

Thanks, but of course it isn't just me.
RAID6 (i.e. double-parity raid) is a good case in point.
That was developed and tested and pushed by Peter Anvin, not at all by me.
I eventually merged his separate raid6main.c into raid5.c and then merged some
of the functions.  So I did some "maintainer" stuff, but didn't do the
development.   It is likely that Triple Parity RAID will only happen if
someone else steps up like Peter did, because I'm really not that interested.

So we don't need feature requests, we need code submissions.

NeilBrown

> 
> 
> Mit freundlichen Grüßen
> Ronny Egner
> --
> Ronny Egner
> Oracle Certified Master 11g (OCM)
>  
> EMail:      ronnyegner@ronnyegner-consulting.de
> <mailto:roonnyegner@ronnyegner-consulting.de>
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html


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Re: Status of Tripe Parity RAID

[David Brown]

On 02/08/14 10:11, Ronny Egner wrote:
> Dear All,
>
> i would like to ask about the status of Tripe Parity RAID.
>
> I´ve found some posts on the list from Andrea Mazzoleni dating back to
> 2013
> but after that nothing seemed to be moving.
>
> If this is currently not on the wish list i would like to add that as
> Feature Request :-)
>
>
> Thanks Neil for this great piece of software.
>

I believe Andrea got the code working for doing the multiple parity raid 
calculations, but I don't know how complete it is.  I have looked at his 
maths, and agree that it is solid - and I think the general opinion is 
that he has found the best algorithms for the task (better than the one 
I came up with, and better than the one used by ZFS for triple parity).

As far as I know, no work has been done on integrating this into the md 
code itself, nor into the mdadm code.

As Neil says, we don't need a feature request on this - it is already 
requested.  We need someone who is able to spend the time putting it 
together.  The mathematical bit is in place, so it doesn't have to be a 
person (or people) who understands that part so well.


David


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