Never ever use osd pool default min size = 1 this will break your neck and does not make sense really. :-) On Mon, Jul 10, 2023 at 7:33 PM Dan van der Ster <dan.vanderster@xxxxxxxxx> wrote: > > Hi Jan, > > On Sun, Jul 9, 2023 at 11:17 PM Jan Marek <jmarek@xxxxxx> wrote: > > > Hello, > > > > I have a cluster, which have this configuration: > > > > osd pool default size = 3 > > osd pool default min size = 1 > > > > Don't use min_size = 1 during regular stable operations. Instead, use > min_size = 2 to ensure data safety, and then you can set the pool to > min_size = 1 manually in the case of an emergency. (E.g. in case the 2 > copies fail and will not be recoverable). > > > > I have 5 monitor nodes and 7 OSD nodes. > > > > 3 monitors is probably enough. Put 2 in the same DC with 2 replicas, and > the other in the DC with 1 replica. > > > > I have changed a crush map to divide ceph cluster to two > > datacenters - in the first one will be a part of cluster with 2 > > copies of data and in the second one will be part of cluster > > with one copy - only emergency. > > > > I still have this cluster in one > > > > This cluster have a 1 PiB of raw data capacity, thus it is very > > expensive add a further 300TB capacity to have 2+2 data redundancy. > > > > Will it works? > > > > If I turn off the 1/3 location, will it be operational? > > > Yes the PGs should be active and accept IO. But the cluster will be > degraded, it cannot stay in this state permanently. (You will need to > recover the 3rd replica or change the crush map). > > > > > I > > believe, it is a better choose, it will. And what if "die" 2/3 > > location? > > > with min_size = 2, the PG wil be inactive. but the data will be safe. If > this happens, then set min_size=1 to activate the PGs. > Mon will not have quorum though -- you need a plan for that. And also plan > where you put your MDSs. > > -- dan > > ______________________________________________________ > Clyso GmbH | Ceph Support and Consulting | https://www.clyso.com > > > > > > On this cluster is pool with cephfs - this is a main > > part of CEPH. > > > > Many thanks for your notices. > > > > Sincerely > > Jan Marek > > -- > > Ing. Jan Marek > > University of South Bohemia > > Academic Computer Centre > > Phone: +420389032080 > > http://www.gnu.org/philosophy/no-word-attachments.cs.html > > _______________________________________________ > > 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 _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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