On 19/06/2014 18:33, Pavel V. Kaygorodov wrote: > > This ruleset works well for replicated pools with size 6 (I have tested it on > data and metadata pools, which I cannot delete). > The erasure pool with k=3 and m=3 must have size 6?
Yes. However, the algorithm is slightly different and depending on the number
of devices you actually have, it may fail where a replicated ruleset works.
>
> Pavel.
>
>> On 19/06/2014 18:17, Pavel V. Kaygorodov wrote:
>>> Hi!
>>>
>>> I want to make erasure-coded pool with k=3 and m=3. Also, I want to
>>> distribute data between two hosts, having 3 osd from host1 and 3 from host2.
>>> I have created a ruleset:
>>>
>>> rule ruleset_3_3 {
>>> ruleset 0
>>> type replicated
You need:
type erasure
>>> min_size 6
>>> max_size 6
>>> step take host1
>>> step chooseleaf firstn 3 type osd
>>> step emit
>>> step take host2
>>> step chooseleaf firstn 3 type osd
>>> step emit
>>> }
Cheers
>> Hi,
>>
>> I suggest you test the ruleset created with crushtool to check if what comes
>> out of it is what you expect. It's quite convenient to use multiple of 10 to
>> visually match the result. For instance
>>
>> crushtool -o /tmp/t.map --num_osds 500 --build node straw 10 datacenter
>> straw 10 root straw 0
>>
>> then you can
>>
>> crushtool -c /tmp/t.txt -o /tmp/t.map ; crushtool -i /tmp/t.map
>> --show-bad-mappings --show-statistics --test --rule 1 --x 1 --num-rep 12
>>
>> This is the general idea and you can find details about this in the
>> crushtool help and the test scripts at
>>
>> https://github.com/ceph/ceph/tree/master/src/test/cli/crushtool
>>
>> for instance
>>
>>
>> https://github.com/ceph/ceph/blob/master/src/test/cli/crushtool/bad-mappings.t
>>
>> which shows what happens when there is a "bad mapping", i.e. the crushmap
>> could not be used to get the number of OSD you want. This is most probably
>> why pg get stuck.
>>
>> Cheers
>>
>>> I have created an erasure code profile:
>>>
>>> ceph osd erasure-code-profile set def33 k=3 m=3
>>>
>>> I have created a pool:
>>>
>>> ceph osd pool create images 2048 2048 erasure def33 ruleset_3_3
>>>
>>> Now I see 2048 pgs permanently in "creating" state.
>>>
>>> What is wrong?
>>>
>>> Pavel.
>>>
>>> _______________________________________________
>>> ceph-users mailing list
>>> [email protected]
>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>
>>
>> --
>> Loïc Dachary, Artisan Logiciel Libre
>>
>
--
Loïc Dachary, Artisan Logiciel Libre
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