Hello everyone, After discussing a few failure scenarios with different people on OFTC network #ceph, I wanted to make sure that the following makes sense. I have 2 Data Centers, please see attachment and I want to make sure that if Data Center 1 (DC1) fails data recovery should be possible on Data Center 2 (DC2) As you can see on the diagram, I have 8 OSD's in total, 4 on each DC. Using an Erasure Coded pool I've set the crush-failure-domain=rack. - 2 DC's - 8 OSD's in total - EC pool profile used crush-device-class= crush-failure-domain=rack crush-root=default jerasure-per-chunk-alignment=false k=2 m=2 plugin=jerasure technique=reed_sol_van w=8 Current crush layout: # ceph osd df tree ID  CLASS WEIGHT  REWEIGHT SIZE    USE     AVAIL   %USE  VAR  PGS TYPE NAME                          -1       1.56238        - 1.6 TiB 280 GiB 1.3 TiB 17.47 1.00   - root default                      -22       0.39059        - 400 GiB  70 GiB 330 GiB 17.48 1.00   -     rack rack1-dc1                 -3       0.19530        - 200 GiB  35 GiB 165 GiB 17.45 1.00   -         host th-dev-ceph-osd-tc01   7   hdd 0.19530  1.00000 200 GiB  35 GiB 165 GiB 17.45 1.00 195             osd.7                  -5       0.19530        - 200 GiB  35 GiB 165 GiB 17.50 1.00   -         host th-dev-ceph-osd-tc02   1   hdd 0.19530  0.98708 200 GiB  35 GiB 165 GiB 17.50 1.00 195             osd.1                 -20       0.39059        - 400 GiB  70 GiB 330 GiB 17.47 1.00   -     rack rack1-dc2                -13       0.19530        - 200 GiB  35 GiB 165 GiB 17.49 1.00   -         host th-dev-ceph-osd-wp01   5   hdd 0.19530  1.00000 200 GiB  35 GiB 165 GiB 17.49 1.00 198             osd.5                 -11       0.19530        - 200 GiB  35 GiB 165 GiB 17.45 1.00   -         host th-dev-ceph-osd-wp02   0   hdd 0.19530  1.00000 200 GiB  35 GiB 165 GiB 17.45 1.00 197             osd.0                 -19       0.39059        - 400 GiB  70 GiB 330 GiB 17.46 1.00   -     rack rack2-dc1                 -7       0.19530        - 200 GiB  35 GiB 165 GiB 17.35 0.99   -         host th-dev-ceph-osd-tc03   2   hdd 0.19530  1.00000 200 GiB  35 GiB 165 GiB 17.35 0.99 198             osd.2                 -15       0.19530        - 200 GiB  35 GiB 165 GiB 17.57 1.01   -         host th-dev-ceph-osd-tc04   6   hdd 0.19530  1.00000 200 GiB  35 GiB 165 GiB 17.57 1.01 198             osd.6                 -21       0.39059        - 400 GiB  70 GiB 330 GiB 17.48 1.00   -     rack rack2-dc2                 -9       0.19530        - 200 GiB  35 GiB 165 GiB 17.46 1.00   -         host th-dev-ceph-osd-wp03   3   hdd 0.19530  1.00000 200 GiB  35 GiB 165 GiB 17.46 1.00 197             osd.3                 -17       0.19530        - 200 GiB  35 GiB 165 GiB 17.50 1.00   -         host th-dev-ceph-osd-wp04   4   hdd 0.19530  1.00000 200 GiB  35 GiB 165 GiB 17.50 1.00 198             osd.4                                      TOTAL 1.6 TiB 280 GiB 1.3 TiB 17.47                                            MIN/MAX VAR: 0.99/1.01  STDDEV: 0.06 I am aware that this is not optimal so please advise. What EC profile should I chose, what should k and m values be and should I use LRC instead of JERASURE algorithm considering the attached jpeg. Thank you very much in advance! -- Met vriendelijke groeten, Kind regards, Valentin Bajrami Target Holding