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
