Reed Solomon coding based Raid?

Reed Solomon coding based Raid?

[John Hendrikx]

I was wondering if there is support for a raid level where one can 
choose the redundancy level.  Raid 5 allows for one redundant drive, 
Raid 6 for two, but there's no raid level that would support arbitrary 
redundancy (even to the point of allowing one to add extra redundancy 
later on, by simply putting spare drives to immediate use).

I'm just a casual Software Raid user, and have been using Raid 6 for a 
small 8 TB array for a few years now and I realize that there's quite 
some CPU overhead involved for such redundancy, but for my purposes 
speed is not a relevant concern (10 MB/sec is enough).

--John

Re: Reed Solomon coding based Raid?

[Kasper Sandberg]

As far as i know, theres not support for this, however, i do believe
raid6 uses reed-solomon.

On Sat, 2009-11-28 at 16:15 +0100, John Hendrikx wrote:
> I was wondering if there is support for a raid level where one can 
> choose the redundancy level.  Raid 5 allows for one redundant drive, 
> Raid 6 for two, but there's no raid level that would support arbitrary 
> redundancy (even to the point of allowing one to add extra redundancy 
> later on, by simply putting spare drives to immediate use).
> 
> I'm just a casual Software Raid user, and have been using Raid 6 for a 
> small 8 TB array for a few years now and I realize that there's quite 
> some CPU overhead involved for such redundancy, but for my purposes 
> speed is not a relevant concern (10 MB/sec is enough).
> 
> --John
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
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Re: Reed Solomon coding based Raid?

[Peter Chacko]

symform, a startup create 32 parity stipes of 64 original stripes, and
distribute the fragments in different geographies.

they call it, RAID-96 And apparently reed-solomon coded.

http://www.symform.com/features-benefits.aspx

thanks

On Sat, Nov 28, 2009 at 9:18 PM, Kasper Sandberg <postmaster@metanurb.dk> wrote:
> As far as i know, theres not support for this, however, i do believe
> raid6 uses reed-solomon.
>
> On Sat, 2009-11-28 at 16:15 +0100, John Hendrikx wrote:
>> I was wondering if there is support for a raid level where one can
>> choose the redundancy level.  Raid 5 allows for one redundant drive,
>> Raid 6 for two, but there's no raid level that would support arbitrary
>> redundancy (even to the point of allowing one to add extra redundancy
>> later on, by simply putting spare drives to immediate use).
>>
>> I'm just a casual Software Raid user, and have been using Raid 6 for a
>> small 8 TB array for a few years now and I realize that there's quite
>> some CPU overhead involved for such redundancy, but for my purposes
>> speed is not a relevant concern (10 MB/sec is enough).
>>
>> --John
>>
>>
>> --
>> 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: Reed Solomon coding based Raid?

[Andrew Dunn]

I have been toying with the idea of an open source project to achieve a 
more generalized functional spec. than what symform has created. I was 
thinking of calling it RAINcloud (redundant array of independent nodes)

I started drawing up the requirements over the holiday weekend.

Peter Chacko wrote:
> symform, a startup create 32 parity stipes of 64 original stripes, and
> distribute the fragments in different geographies.
>
> they call it, RAID-96 And apparently reed-solomon coded.
>
> http://www.symform.com/features-benefits.aspx
>
> thanks
>
> On Sat, Nov 28, 2009 at 9:18 PM, Kasper Sandberg <postmaster@metanurb.dk> wrote:
>   
>> As far as i know, theres not support for this, however, i do believe
>> raid6 uses reed-solomon.
>>
>> On Sat, 2009-11-28 at 16:15 +0100, John Hendrikx wrote:
>>     
>>> I was wondering if there is support for a raid level where one can
>>> choose the redundancy level.  Raid 5 allows for one redundant drive,
>>> Raid 6 for two, but there's no raid level that would support arbitrary
>>> redundancy (even to the point of allowing one to add extra redundancy
>>> later on, by simply putting spare drives to immediate use).
>>>
>>> I'm just a casual Software Raid user, and have been using Raid 6 for a
>>> small 8 TB array for a few years now and I realize that there's quite
>>> some CPU overhead involved for such redundancy, but for my purposes
>>> speed is not a relevant concern (10 MB/sec is enough).
>>>
>>> --John
>>>
>>>
>>> --
>>> 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
>>>       
>> --
>> 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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>
>   

-- 
Andrew Dunn
http://agdunn.net

Re: Reed Solomon coding based Raid?

[Goswin von Brederlow]

Andrew Dunn <andrew.g.dunn@gmail.com> writes:

> I have been toying with the idea of an open source project to achieve
> a more generalized functional spec. than what symform has created. I
> was thinking of calling it RAINcloud (redundant array of independent
> nodes)
>
> I started drawing up the requirements over the holiday weekend.

Would that be nodes as in different systems? In that case you should
check glusterfs and provide a raincloud module for it.

On the other hand if nodes is just local disks glusterfs might still
be a good way to implement and test your algorithm before putting it
into the kernel.

MfG
        Goswin

PS: Isn't the Reed Solomon for x+1 disks == XOR and x+2 disks p+q
parity? I.e. raid4/5/6 are Reed Solomon are just the first 2 cases for
Reed Solomon.

Re: Reed Solomon coding based Raid?

[Keld Simonsen]

On Sat, Nov 28, 2009 at 04:15:28PM +0100, John Hendrikx wrote:
> I was wondering if there is support for a raid level where one can 
> choose the redundancy level.  Raid 5 allows for one redundant drive, 
> Raid 6 for two, but there's no raid level that would support arbitrary 
> redundancy (even to the point of allowing one to add extra redundancy 
> later on, by simply putting spare drives to immediate use).
> 
> I'm just a casual Software Raid user, and have been using Raid 6 for a 
> small 8 TB array for a few years now and I realize that there's quite 
> some CPU overhead involved for such redundancy, but for my purposes 
> speed is not a relevant concern (10 MB/sec is enough).

Actually you can choose the number of copies in raid10, via the -n
option. 

Best regards
keld