Hi Pierre,

Thanks for the pointer to
https://github.com/rozofs/rozofs/blob/master/rozofs/common/transform.c
https://github.com/rozofs/rozofs/blob/master/rozofs/common/transform.h
If I understand correctly these are the core functions implementing the 
algorithm. Would you advise to expose these three functions so that a third 
party software such as ceph use it ? Or are there more high level functions 
that are easier to use to do something like:

 encode(char* buffer_in, char* buffer_out[])
 decode(char* buffer_in[], char* buffer_out) 
 repair(char* buffer_in[], char* buffer_out, int indices_of_damaged_buffers[])

Cheers

On 05/30/2013 05:49 PM, Loic Dachary wrote:
> Hi Pierre,
> 
> I took a look at 
> https://github.com/rozofs/rozofs/blob/master/src/rozofsmount/rozofsmount.c#L1557
> and it gave me a high level view of the fuse bindings of rozofs, thanks for 
> this :-)
> 
> I'm now looking into the functions that could be wrapped into a library 
> implementing Mojette Transform so that it could be used by rozofs and ceph. 
> Which file would you recommend I study for bootstraping this effort ?
> 
> Cheers
> 
> 
> On 05/29/2013 05:23 PM, Pierre Evenou wrote:
>> 2013/5/29 Loic Dachary <[email protected] <mailto:[email protected]>>
>>
>>     Hi Pierre,
>>
>>     As discussed today over the phone, I'm very much interested in trying to 
>> reuse the Mojette Transform implementation in the context of the work 
>> related to the implementation of an erasure coded backend in Ceph. The 
>> progress can be tracked from http://tracker.ceph.com/issues/5046 and the 
>> sub-tickets and the original discussion from the last Ceph summit is at 
>> http://wiki.ceph.com/01Planning/02Blueprints/Dumpling/Erasure_encoding_as_a_storage_backend
>>
>>
>> Thanks for the links.
>>  
>>
>>     I was reading the code of rbs_restore_one_rb_entry at
>>     https://github.com/rozofs/rozofs/blob/master/src/storaged/rbs.c#L104
>>     and assumed the implementation is in
>>     https://github.com/rozofs/rozofs/blob/master/src/storaged/rbs_transform.h
>>     
>> https://github.com/rozofs/rozofs/blob/master/src/storaged/rbs_transform.cc
>>
>>     And also tried to understand 
>> http://en.wikipedia.org/wiki/Mojette_Transform and bought "The Mojette 
>> Transform: Theory and Applications" 
>> http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1848210809.html in the 
>> hope to get more sense out of it ;-)
>>
>>     Is there a part of the rozofs code you would advise me to read first in 
>> order to understand how it works ?
>>
>>
>> I would recommend to have a look to rozofsmount.c witch is a key part in 
>> RozoFS.
>>  
>>
>>     Cheers
>>
>>     --
>>     Loïc Dachary, Artisan Logiciel Libre
>>     All that is necessary for the triumph of evil is that good people do 
>> nothing.
>>
>>
>>
>>
>> -- 
>> Pierre Evenou│+33.7.60.09.08.80│[email protected] 
>> <mailto:[email protected]>│www.rozofs.com <http://www.rozofs.com/>
> 

-- 
Loïc Dachary, Artisan Logiciel Libre
All that is necessary for the triumph of evil is that good people do nothing.

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