On Thu, Nov 17, 2016 at 6:14 PM, Sebastien Han <shan@xxxxxxxxxx> wrote: > Hey, > > I was wondering, since we have PG calc online to decide the right > value for our PGs per pool. The logic seems to be easy and well > understood. Looks like a simple calculation, I don't see anything like > depending on a use case we are changing the value or anything. > > Any reason why this logic is not part of Ceph? > Mons know about everything on the cluster and since they manage pool > creations they should be able to take the right decision. > > Am I missing something? I think the reason nobody has done this so far is that there's no overall (multiple pools at a time) setup interface in Ceph. To do the pg calc stuff, you need a user to tell you not just that they want a pool, but how many pools they want and what they will use them for: something friendlier than the current "osd pool create" command can handle. Having mons do any kind of guessing on a "pool at a time" basis without visibility of the user's overall intent is pretty dangerous, because users can never fix a bad automatic choice (can't decrease pg_num). John > Thanks! > > -- > Cheers > > –––––– > Sébastien Han > Principal Storage Architect > > "Always give 100%. Unless you're giving blood." > > Mail: seb@xxxxxxxxxx > Address: 11 bis, rue Roquépine - 75008 Paris > -- > 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 -- 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
