Re: How to get Active set of OSD Map in serial order of osd index

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Think of the osd numbers as names.  The plugin interface doesn't even
tell you which shard maps to which osd.  Why would it make a
difference?
-Sam

On Wed, Jul 27, 2016 at 12:45 AM, Syed Hussain <syed789@xxxxxxxxx> wrote:
> Fundamentally, I wanted to know what chunks are allocated in which OSDs.
> This way I can preserve the array structure required for my
> Erasure Code. If all the chunks are placed in randomly ordered OSDs (like in
> Jerasure or ISA) then I loss that array structure required in the
> Encoding/Decoding algorithm of my Plugin.
> I'm trying to develop an Erasure Code plugin for RDP (or RAID-DP) kind of
> code.
>
> Thanks,
> Syed
>
> On Wed, Jul 27, 2016 at 4:12 AM, Samuel Just <sjust@xxxxxxxxxx> wrote:
>>
>> Why do you want them in serial increasing order?
>> -Sam
>>
>> On Tue, Jul 26, 2016 at 2:43 PM, Samuel Just <sjust@xxxxxxxxxx> wrote:
>>>
>>> How would such a code work if there were more than 24 osds?
>>> -Sam
>>>
>>> On Tue, Jul 26, 2016 at 2:37 PM, Syed Hussain <syed789@xxxxxxxxx> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I'm working to develop an Erasure Code plugin (variation of ISA) that
>>>> have typical requirement that the active set of the Erasure Coded pool in
>>>> serial order.
>>>> For example,
>>>>
>>>> ====================================================================================================
>>>> >ceph osd erasure-code-profile set reed_k16m8_isa k=16 m=8 plugin=isa
>>>> > technique=reed_sol_van ruleset-failure-domain=osd
>>>> >ceph osd pool create reed_k16m8_isa_pool 128 128 erasure reed_k16m8_isa
>>>> >echo "ABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHIABCDEFGHI" | rados
>>>> > --pool reed_k16m8_isa_pool put myobj16_8 -
>>>> >ceph osd map reed_k16m8_isa_pool myobj16_8
>>>> osdmap e86 pool 'reed_k16m8_isa_pool' (1) object 'myobj16_8' -> pg
>>>> 1.cf6ec86f (1.6f) -> up
>>>> ([4,23,22,10,9,11,15,6,19,1,7,8,17,21,16,14,18,12,13,20,3,5,0,2], p4) acting
>>>> ([4,23,22,10,9,11,15,6,19,1,7,8,17,21,16,14,18,12,13,20,3,5,0,2], p4)
>>>>
>>>> ====================================================================================================
>>>>
>>>> That means the chunks 0, 1, 2, ...23 of the erasure coding are saved int
>>>> osd 4, 23, 22, 10, ...2 respectively as per the order given in the active
>>>> set.
>>>>
>>>> Now my question is how I'll be able to get the PG map for object
>>>> myobj16_8 having active set as: [0, 1, 2, ...23] so that the i-th chunk of
>>>> the Erasure Coded object saves into
>>>> i-th osd.
>>>>
>>>> Is there any option available in "ceph osd pool create" to do it?
>>>> Or there may be other way available to accomplish this case.
>>>>
>>>> Appreciate your suggestions..
>>>>
>>>> Thanks,
>>>> Syed Hussain
>>>> NetWorld
>>>>
>>>> _______________________________________________
>>>> ceph-users mailing list
>>>> ceph-users@xxxxxxxxxxxxxx
>>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>>
>>>
>>
>
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