There are cerrtain sequences of events that can result in Ceph not knowing which copy of a PG (if any) has the current information. That’s one way you can effectively lose data. I ran into it myself last year on a legacy R2 cluster. If you *must* have a 2:1 raw:usable ratio, you’re better off with 2,2 EC. Asuming you have at least 4 failure domains. > > There are only two ways that size=2 can go: > A) You set min_size=1 and risk data loss > B) You set min_size=2 and your cluster stops every time you lose a > drive or reboot a machine > > Neither of these are good options for most use cases; but there's > always an edge case. You should stay with size=3, min_size=2 unless > you have an unusual use case. > > On Tue, Aug 17, 2021 at 10:33 AM Michel Niyoyita <micou12@xxxxxxxxx> wrote: >> >> Hi all , >> >> Going to deploy a ceph cluster in production with replicas size of 2 . Is >> there any inconvenience on the service side ? I am going to change the >> default (3) to 2. >> >> Please advise. >> >> Regards. >> >> Michel >> _______________________________________________ >> 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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