Re: erasure pool with isa plugin

[Loic Dachary <loic@dachary.org>]

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Hi,

On 23/06/2015 06:06, Gregory Farnum wrote:
> On Mon, Jun 22, 2015 at 10:34 PM, Loic Dachary <loic@dachary.org> wrote:
>> Hi Tom,
>>
>> On 22/06/2015 17:10, Deneau, Tom wrote:
>>> If one has a cluster with some nodes that can run with the ISA plugin
>>> and some that cannot, is there a way to define a pool such that the
>>> ISA-capable nodes can use the ISA plugin and the others can use say
>>> the jerasure plugin?
>>
>> There is no way to do that, because there is no guarantee that an object encoded by jerasure can be decoded by isa and vice versa.
> 
> Shouldn't we be able to set up something that *does* guarantee that,
> though? Either by combining them into a single plugin which
> dynamically configures to the fastest possible for that machine, or by
> running them against the same object corpus and requiring that they
> produce the same output?

I don't know enough about the maths involved to evaluate how difficult it is. Although both implement Reed Solomon using Vandermonde or Cauchy matrices, I think there are details that makes the output different. 

Cheers

> -Greg
> 

-- 
Loïc Dachary, Artisan Logiciel Libre


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