Hi Sam, Is there a branch somewhere where you have defined a config_opts for the desired strip size / chunk size ?
Cheers On 02/02/2014 23:28, Samuel Just wrote: > That looks about right to me. It's handy to have a "ground truth" for > everyone to ensure that they agree with. > -Sam > > On Sun, Feb 2, 2014 at 7:06 AM, Loic Dachary <[email protected]> wrote: >> [cc' ceph-devel] >> >> Hi Sam, >> >> Assuming https://github.com/ceph/ceph/pull/1144 gets merged, MONs can query >> the plugin for a given pool or crush ruleset conveniently: >> >> https://github.com/dachary/ceph/blob/15c90fbf61445063967fc80ee1c916d70c593a54/src/mon/OSDMonitor.cc#L2803 >> >> ErasureCodeInterfaceRef erasure_code; >> err = get_erasure_code(properties, &erasure_code, ss); >> if (err == 0) >> *size = erasure_code->get_chunk_count(); >> >> And OSDs can do something similar (and must whenever an erasure coded pool >> is instantiated). If I understood correctly, you would like the result of >> erasure_code->get_chunk_size(some_osd_config_opt_value_defining_the_stripe_size) >> to be set as a new value in pg_pool_t >> https://github.com/dachary/ceph/blob/15c90fbf61445063967fc80ee1c916d70c593a54/src/osd/osd_types.h#L700 >> when the pool is created. >> >> The benefit of having pg_pool_t::chunk_size would be >> >> a) the value is shared cluster wide and does not depend on the specific >> version of the OSD/MON >> b) if the value is needed frequently in a context where the plugin would >> have to be loaded, this will improve performances >> >> However, whenever an OSD instantiates a PG that belongs to a pool, it must >> assert that the get_chunk_count() returned by the plugin matches the value >> stored in pg_pool_t::chunk_size otherwise it will encode inconsistently. >> >> If my reasoning matches yours, I'll implement the change. Otherwise, please >> correct me :-) >> >> Cheers >> >> -- >> Loïc Dachary, Artisan Logiciel Libre >> > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Loïc Dachary, Artisan Logiciel Libre
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