On 11/03/2014 13:21, John Spray wrote: > From a high level view, what is the logical difference between the > crush ruleset and the properties object? I'm thinking about how this > is exposed to users and tools, and it seems like both would be defined > as "the settings about data placement and encoding". I certainly > understand the separation internally, I am just concerned about making > the interface we expose upwards more complicated by adding a new type > of object. > > Is there really a need for a new type of properties object, instead of > storing these properties under the existing ruleset ID? These properties are used to configure the new feature that was introduced in Firefly : erasure coded pools. From a user point of view the simplest would be to ceph osd pool create mypool erasure and rely on the fact that a default ruleset will be created using the default erasure code plugin with the default parameters. If the sysadmin wants to tweak the K+M factors (s)he could: ceph osd set properties myproperties k=10 m=4 and then ceph osd pool create mypool erasure myproperties which would implicitly ask the default erasure code plugin to create a ruleset named "mypool-ruleset" after configuring it with myproperties. If the sysadmin wants to share rulesets between pools instead of relying on their implicit creation, (s)he could ceph osd create-serasure myruleset myproperties and then ceph osd set crush_ruleset as per usual. And if (s)he really wants fine tuning, manually adding the ruleset is also possible. I feel confortable explaining this but I'm probably much too familiar with the subject to be a good judge of what makes sense to someone new or not ;-) Cheers > > John > > > On Sun, Mar 9, 2014 at 12:13 PM, Loic Dachary > <loic.dachary@xxxxxxxxxxxxx> wrote: >> Hi Sage & Sam, >> >> I quickly sketched the replacement of the pg_pool_t::properties map with a OSDMap::properties list of maps at https://github.com/dachary/ceph/commit/fe3819a62eb139fc3f0fa4282b4d22aecd8cd398 and explained how I see it at http://tracker.ceph.com/issues/7662#note-2 >> >> It indeed makes things simpler, more consistent and easier to explain. I can provide an implementation this week if this seems reasonable to you. >> >> Cheers >> >> -- >> Loďc Dachary, Senior Developer >> >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- Loïc Dachary, Senior Developer -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
