More on the subject can be found here: https://ceph.com/geen-categorie/difference-between-ceph-osd-reweight-and-ceph-osd-crush-reweight/
On Fri, Mar 1, 2019 at 2:22 PM Darius Kasparavičius <daz...@gmail.com> wrote: > > Hi, > > Setting crush weight to 0 removes the osds weight from crushmap, by > modifying hosts total weight. Which forces rebalancing of data across > all the cluster. Setting and OSD to out only modifies "REWEIGHT" > status, which balances data inside the same host. > > On Fri, Mar 1, 2019 at 12:25 PM Paul Emmerich <paul.emmer...@croit.io> wrote: > > > > On Fri, Mar 1, 2019 at 11:17 AM Fyodor Ustinov <u...@ufm.su> wrote: > > > May be. But "ceph out + ceph osd purge" causes double relocation, and > > > "ceph reweight 0 + ceph osd purge" - causes only one. > > > > No, the commands "ceph osd out X" and "ceph osd reweight X 0" do the > > exact same thing: both set reweight to 0. > > > > Paul > > > > > > > > ----- Original Message ----- > > > From: "Paul Emmerich" <paul.emmer...@croit.io> > > > To: "Fyodor Ustinov" <u...@ufm.su> > > > Cc: "David Turner" <drakonst...@gmail.com>, "ceph-users" > > > <ceph-users@lists.ceph.com> > > > Sent: Friday, 1 March, 2019 11:54:20 > > > Subject: Re: [ceph-users] Right way to delete OSD from cluster? > > > > > > "out" is internally implemented as "reweight 0" > > > > > > Paul > > > > > > -- > > > Paul Emmerich > > > > > > Looking for help with your Ceph cluster? Contact us at https://croit.io > > > > > > croit GmbH > > > Freseniusstr. 31h > > > 81247 München > > > www.croit.io > > > Tel: +49 89 1896585 90 > > > > > > On Fri, Mar 1, 2019 at 10:48 AM Fyodor Ustinov <u...@ufm.su> wrote: > > > > > > > > Hi! > > > > > > > > As far as I understand, reweight also does not lead to the situation "a > > > > period where one copy / shard > > > > is missing". > > > > > > > > ----- Original Message ----- > > > > From: "Paul Emmerich" <paul.emmer...@croit.io> > > > > To: "Fyodor Ustinov" <u...@ufm.su> > > > > Cc: "David Turner" <drakonst...@gmail.com>, "ceph-users" > > > > <ceph-users@lists.ceph.com> > > > > Sent: Friday, 1 March, 2019 11:32:54 > > > > Subject: Re: [ceph-users] Right way to delete OSD from cluster? > > > > > > > > On Fri, Mar 1, 2019 at 8:55 AM Fyodor Ustinov <u...@ufm.su> wrote: > > > > > > > > > > Hi! > > > > > > > > > > Yes. But I am a little surprised by what is written in the > > > > > documentation: > > > > > > > > the point of this is that you don't have a period where one copy/shard > > > > is missing if you wait for it to take it out. > > > > Yeah, there'll be an unnecessary small data movement afterwards, but > > > > you are never missing a copy. > > > > > > > > > > > > Paul > > > > > > > > > http://docs.ceph.com/docs/mimic/rados/operations/add-or-rm-osds/ > > > > > > > > > > --- > > > > > Before you remove an OSD, it is usually up and in. You need to take > > > > > it out of the cluster so that Ceph can begin rebalancing and copying > > > > > its data to other OSDs. > > > > > ceph osd out {osd-num} > > > > > [...] > > > > > --- > > > > > > > > > > That is, it is argued that this is the most correct way (otherwise it > > > > > would not have been written in the documentation). > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > From: "David Turner" <drakonst...@gmail.com> > > > > > To: "Fyodor Ustinov" <u...@ufm.su> > > > > > Cc: "Scottix" <scot...@gmail.com>, "ceph-users" > > > > > <ceph-users@lists.ceph.com> > > > > > Sent: Friday, 1 March, 2019 05:13:27 > > > > > Subject: Re: [ceph-users] Right way to delete OSD from cluster? > > > > > > > > > > The reason is that an osd still contributes to the host weight in the > > > > > crush > > > > > map even while it is marked out. When you out and then purge, the > > > > > purging > > > > > operation removed the osd from the map and changes the weight of the > > > > > host > > > > > which changes the crush map and data moves. By weighting the osd to > > > > > 0.0, > > > > > the hosts weight is already the same it will be when you purge the > > > > > osd. > > > > > Weighting to 0.0 is definitely the best option for removing storage > > > > > if you > > > > > can trust the data on the osd being removed. > > > > > > > > > > On Tue, Feb 26, 2019, 3:19 AM Fyodor Ustinov <u...@ufm.su> wrote: > > > > > > > > > > > Hi! > > > > > > > > > > > > Thank you so much! > > > > > > > > > > > > I do not understand why, but your variant really causes only one > > > > > > rebalance > > > > > > compared to the "osd out". > > > > > > > > > > > > ----- Original Message ----- > > > > > > From: "Scottix" <scot...@gmail.com> > > > > > > To: "Fyodor Ustinov" <u...@ufm.su> > > > > > > Cc: "ceph-users" <ceph-users@lists.ceph.com> > > > > > > Sent: Wednesday, 30 January, 2019 20:31:32 > > > > > > Subject: Re: [ceph-users] Right way to delete OSD from cluster? > > > > > > > > > > > > I generally have gone the crush reweight 0 route > > > > > > This way the drive can participate in the rebalance, and the > > > > > > rebalance > > > > > > only happens once. Then you can take it out and purge. > > > > > > > > > > > > If I am not mistaken this is the safest. > > > > > > > > > > > > ceph osd crush reweight <id> 0 > > > > > > > > > > > > On Wed, Jan 30, 2019 at 7:45 AM Fyodor Ustinov <u...@ufm.su> wrote: > > > > > > > > > > > > > > Hi! > > > > > > > > > > > > > > But unless after "ceph osd crush remove" I will not got the > > > > > > > undersized > > > > > > objects? That is, this is not the same thing as simply turning off > > > > > > the OSD > > > > > > and waiting for the cluster to be restored? > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > > From: "Wido den Hollander" <w...@42on.com> > > > > > > > To: "Fyodor Ustinov" <u...@ufm.su>, "ceph-users" < > > > > > > ceph-users@lists.ceph.com> > > > > > > > Sent: Wednesday, 30 January, 2019 15:05:35 > > > > > > > Subject: Re: [ceph-users] Right way to delete OSD from cluster? > > > > > > > > > > > > > > On 1/30/19 2:00 PM, Fyodor Ustinov wrote: > > > > > > > > Hi! > > > > > > > > > > > > > > > > I thought I should first do "ceph osd out", wait for the end > > > > > > relocation of the misplaced objects and after that do "ceph osd > > > > > > purge". > > > > > > > > But after "purge" the cluster starts relocation again. > > > > > > > > > > > > > > > > Maybe I'm doing something wrong? Then what is the correct way to > > > > > > delete the OSD from the cluster? > > > > > > > > > > > > > > > > > > > > > > You are not doing anything wrong, this is the expected behavior. > > > > > > > There > > > > > > > are two CRUSH changes: > > > > > > > > > > > > > > - Marking it out > > > > > > > - Purging it > > > > > > > > > > > > > > You could do: > > > > > > > > > > > > > > $ ceph osd crush remove osd.X > > > > > > > > > > > > > > Wait for all good > > > > > > > > > > > > > > $ ceph osd purge X > > > > > > > > > > > > > > The last step should then not initiate any data movement. > > > > > > > > > > > > > > Wido > > > > > > > > > > > > > > > WBR, > > > > > > > > Fyodor. > > > > > > > > _______________________________________________ > > > > > > > > ceph-users mailing list > > > > > > > > ceph-users@lists.ceph.com > > > > > > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > > > > > > > > > > _______________________________________________ > > > > > > > ceph-users mailing list > > > > > > > ceph-users@lists.ceph.com > > > > > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > T: @Thaumion > > > > > > IG: Thaumion > > > > > > scot...@gmail.com > > > > > > _______________________________________________ > > > > > > ceph-users mailing list > > > > > > ceph-users@lists.ceph.com > > > > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > > > > > > _______________________________________________ > > > > > ceph-users mailing list > > > > > ceph-users@lists.ceph.com > > > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
