On 06/02/15 21:07, Udo Lembke wrote: > Am 06.02.2015 09:06, schrieb Hector Martin: >> On 02/02/15 03:38, Udo Lembke wrote: >>> With 3 hosts only you can't survive an full node failure, because for >>> that you need >>> host >= k + m. >> >> Sure you can. k=2, m=1 with the failure domain set to host will survive >> a full host failure. >> > > Hi, > Alexandre has the requirement of 2 failed disk or one full node failure. > This is the reason why I wrote, that this is not possible... But it is, I just explained how that can be achieved with only 3 nodes, with k=4, m=2, and a custom CRUSH rule. Placing precisely two chunks on each host, on two distinct OSDs, satisfies this requirement: any two OSDs can fail (leaving 4/6 chunks) or any host can fail (again leaving 4/6 chunks). -- Hector Martin (hector@xxxxxxxxxxxxxx) Public Key: https://marcan.st/marcan.asc _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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