On Mon, Oct 17, 2022 at 4:40 AM Enrico Bocchi <enrico.bocchi@xxxxxxx> wrote: > > Hi, > > I have played with stretch clusters a bit but never managed to > un-stretch them fully. > > From my experience (using Pacific 16.2.9), once the stretch mode is > enabled, the replicated pools switch to the stretch_rule with size 4, > min_size 2, and require at least one replica in each datacenter. > If one of the two DCs fails, you will still be able to change the crush > rule of your pools back to the traditional replicated rule, and set size > 3, min_size 2. After recovery, your objects won't be degraded anymore > and stored 3 replicas in the surviving DC, but the cluster would still > complain about one DC down (with related osds and mons). > > It does not seem to exist a 'ceph mon disable_stretch_mode' and the > monmaptool does not implement actions to disable stretch mode and remove > the tiebreaker mon. > > I'd be curious to know if it is possible to disable stretch_mode > completely too. Unfortunately, turning it off never got implemented. If somebody's interested, I don't think this would be too hard to implement; the issue is mostly the QA around the feature. :) -Greg > > Cheers, > Enrico > > > On 10/17/22 13:09, Eugen Block wrote: > > Hi, > > > > I didn't have the time to play with it yet, but couldn't you just > > assign a different ruleset to the pool(s)? Or does ceph complain and > > prevent that? I'm not sure if stretch mode will be still active after > > changing the crush rule. But I'm not aware that there's a command to > > revert this: > > > > $ ceph mon enable_stretch_mode e stretch_rule datacenter > > > > But it does use the "stretch_rule" defined, so maybe additionally > > delete that rule? Or start from scratch. ;-) > > > > Regards, > > Eugen > > > > > > Zitat von Manuel Lausch <manuel.lausch@xxxxxxxx>: > > > >> Hi, > >> > >> > >> I am playing around with ceph_stretch_mode and now I have one question: > >> > >> Is it possible to disable stretchmode again? I didn't found anything > >> about this in the documentation. > >> > >> > >> -> Ceph pacific 16.2.9 > >> > >> > >> > >> Manuel > >> _______________________________________________ > >> ceph-users mailing list -- ceph-users@xxxxxxx > >> To unsubscribe send an email to ceph-users-leave@xxxxxxx > > > > > > > > _______________________________________________ > > ceph-users mailing list -- ceph-users@xxxxxxx > > To unsubscribe send an email to ceph-users-leave@xxxxxxx > > -- > Enrico Bocchi > CERN European Laboratory for Particle Physics > IT - Storage & Data Management - General Storage Services > Mailbox: G20500 - Office: 31-2-010 > 1211 Genève 23 > Switzerland > > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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