Re: Triple parity and beyond

[David Brown <david.brown@hesbynett.no>]

On 19/11/13 19:12, Piergiorgio Sartor wrote:
> On Mon, Nov 18, 2013 at 11:08:59PM +0100, Andrea Mazzoleni wrote:

<snip for brevity>

> 
> Hi Andrea,
> 
> great job, this was exactly what I was looking for.
> 
> Do you know if there is a "fast" way not to correct
> errors, but to find them?
> 
> In RAID-6 (as per raid6check) there is an easy way
> to verify where an HDD has incorrect data.
> 

I think the way to do that is just to generate the parity blocks from
the data blocks, and compare them to the existing parity blocks.

> I suspect, for each 2 parity block it should be
> possible to find 1 error (and if this is true, then
> quad parity is more attractive than triple one).
> 
> Furthermore, my second (of first) target would
> be something like: http://www.symform.com/blog/tag/raid-96/
> 
> Which uses 32 parities (out of 96 "disks").

I believe Andrea's matrix is extensible as long as you have no more than
257 disks in total.  A mere 32 parities should not be a problem :-)

mvh.,

David


> 
> Keep going!!!
> 
> bye,
> 
> pg
> 
>>
>> Ciao,
>> Andrea
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