Hello, On Wed, 21 Dec 2016 04:12:56 +0000 Adrian Saul wrote: > > I found the other day even though I had 0 weighted OSDs, there was still weight in the containing buckets which triggered some rebalancing. > > Maybe it is something similar, there was weight added to the bucket even though the OSD underneath was 0. > Maybe, but I checked with "osd tree" before and after the addition and the weights did not change for any of the existing OSDs, nor the host or root bucket(s). At least as far as that output was concerned. I'm partial to this being a floating point rounding error of sorts, which also explains an OSD set to a weight of 0.65 to be listed as "0.64999". Christian > > > -----Original Message----- > > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of > > Christian Balzer > > Sent: Wednesday, 21 December 2016 12:39 PM > > To: ceph-users@xxxxxxxxxxxxxx > > Subject: When Zero isn't 0 (Crush weight mysteries) > > > > > > Hello, > > > > I just (manually) added 1 OSD each to my 2 cache-tier nodes. > > The plan was/is to actually do the data-migration at the least busiest day in > > Japan, New Years (the actual holiday is January 2nd this year). > > > > So I was going to have everything up and in but at weight 0 initially. > > > > Alas at the "ceph osd crush add osd.x0 0 host=ceph-0x" steps Ceph happily > > started to juggle a few PGs (about 7 total) around, despite of course no > > weight in the cluster changing at all. > > No harm done (this is the fast and not too busy cache-tier after all), but very > > much unexpected. > > > > So which part of the CRUSH algorithm goes around and pulls weights out of > > thin air? > > > > Christian > > -- > > Christian Balzer Network/Systems Engineer > > chibi@xxxxxxx Global OnLine Japan/Rakuten Communications > > http://www.gol.com/ > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > Confidentiality: This email and any attachments are confidential and may be subject to copyright, legal or some other professional privilege. They are intended solely for the attention and use of the named addressee(s). They may only be copied, distributed or disclosed with the consent of the copyright owner. If you have received this email by mistake or by breach of the confidentiality clause, please notify the sender immediately by return email and delete or destroy all copies of the email. Any confidentiality, privilege or copyright is not waived or lost because this email has been sent to you by mistake. > -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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