There are four hosts in the environment, the storage pool use EC 4+2, and the Crush rule is configured to select two osds from each host. When I shut down one host, all osds are marked as out state, but PG cannot restore active+clean. Why PG cannot map OSD on another host, Is there a problem with this situation? ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF -1 30.00000 root default -5 7.00000 host host0 0 ssd 1.00000 osd.0 down 0 1.00000 1 ssd 1.00000 osd.1 down 0 1.00000 2 ssd 1.00000 osd.2 down 0 1.00000 3 ssd 1.00000 osd.3 down 0 1.00000 4 ssd 1.00000 osd.4 down 0 1.00000 5 ssd 1.00000 osd.5 down 0 1.00000 6 ssd 1.00000 osd.6 down 0 1.00000 -7 7.00000 host host1 7 ssd 1.00000 osd.7 up 1.00000 1.00000 8 ssd 1.00000 osd.8 up 1.00000 1.00000 9 ssd 1.00000 osd.9 up 1.00000 1.00000 10 ssd 1.00000 osd.10 up 1.00000 1.00000 11 ssd 1.00000 osd.11 up 1.00000 1.00000 12 ssd 1.00000 osd.12 up 1.00000 1.00000 13 ssd 1.00000 osd.13 up 1.00000 1.00000 -9 8.00000 host host2 14 ssd 1.00000 osd.14 up 1.00000 1.00000 15 ssd 1.00000 osd.15 up 1.00000 1.00000 16 ssd 1.00000 osd.16 up 1.00000 1.00000 17 ssd 1.00000 osd.17 up 1.00000 1.00000 18 ssd 1.00000 osd.18 up 1.00000 1.00000 19 ssd 1.00000 osd.19 up 1.00000 1.00000 20 ssd 1.00000 osd.20 up 1.00000 1.00000 21 ssd 1.00000 osd.21 up 1.00000 1.00000 -11 8.00000 host host3 29 1.00000 osd.29 up 1.00000 1.00000 22 ssd 1.00000 osd.22 up 1.00000 1.00000 23 ssd 1.00000 osd.23 up 1.00000 1.00000 24 ssd 1.00000 osd.24 up 1.00000 1.00000 25 ssd 1.00000 osd.25 up 1.00000 1.00000 26 ssd 1.00000 osd.26 up 1.00000 1.00000 27 ssd 1.00000 osd.27 up 1.00000 1.00000 28 ssd 1.00000 osd.28 up 1.00000 1.00000 cluster: id: d24174ae-a1bf-43f9-a8f3-a10246988ab7 health: HEALTH_WARN Reduced data availability: 413 pgs inactive Degraded data redundancy: 414 pgs undersized services: mon: 1 daemons, quorum a mgr: x(active) osd: 30 osds: 23 up, 23 in; 3 remapped pgs data: pools: 1 pools, 512 pgs objects: 0 objects, 0 bytes usage: 24026 MB used, 206 GB / 230 GB avail pgs: 80.664% pgs not active 413 undersized+peered 96 active+clean 2 active+clean+remapped 1 active+undersized+remapped The Ceph environment configuration is as follows: Crush rule: rule ec_4_2 { id 1 type erasure min_size 3 max_size 6 step set_chooseleaf_tries 5 step set_choose_tries 400 step take default step choose indep 0 type host step chooseleaf indep 2 type osd step emit } Pool: pool 1 'ec_4_2' erasure size 6 min_size 5 origin_min_size 0 crush_rule 1 object_hash rjenkins pg_num 512 pgp_num 512 last_change 94 flags hashpspool stripe_width 16384 -------------- ningt0509@xxxxxxxxx