Hello, On Wed, 17 Feb 2016 13:44:17 +0000 Ed Rowley wrote: > On 17 February 2016 at 12:04, Christian Balzer <chibi@xxxxxxx> wrote: > > > > Hello, > > > > On Wed, 17 Feb 2016 11:18:40 +0000 Ed Rowley wrote: > > > >> Hi, > >> > >> We have been running Ceph in production for a few months and looking > >> at our first big expansion. We are going to be adding 8 new OSDs > >> across 3 hosts to our current cluster of 13 OSD across 5 hosts. We > >> obviously want to minimize the amount of disruption this is going to > >> cause but we are unsure about the impact on the crush map as we add > >> each OSD. > >> > > So you are adding new hosts as well? > > > > Yes, we are adding 2 new hosts with 3 OSDs and adding two drives/OSDs > to an existing host > Nods. > >> From the docs I can see that an OSD is added as 'in' and 'down' and > >> wont get objects until the OSD service has started. But what happens > >> to the crushmap while the OSD is 'down', is it recalculated? are > >> objects misplaced and moved on the existing cluster? > >> > > Yes, even more so when adding hosts (well, the first OSD on a new > > host). > > > > Find my "Storage node refurbishing, a "freeze" OSD feature would be > > nice" thread in the ML archives. > > > > Christian > > > > Thanks for the reference, the thread is useful, > > I am right with the assumption that adding an OSD with: > > [osd] > osd_crush_initial_weight = 0 > Or by adding it with a weight of zero like this: ceph osd crush add <osdnumber> 0 host=<osdhost> > will not change the existing crush map > Well it will change it (ceph osd tree will show it), but no data movement will result from it, yes. Christian > > >> We think we would like to limit the rebuild of the crush map, is this > >> possible or beneficial. > >> > >> Thanks, > >> > >> Ed Rowley > >> _______________________________________________ > >> ceph-users mailing list > >> ceph-users@xxxxxxxxxxxxxx > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >> > > > > > > -- > > Christian Balzer Network/Systems Engineer > > chibi@xxxxxxx Global OnLine Japan/Rakuten Communications > > http://www.gol.com/ > > Regards, > > Ed Rowley > -- 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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