Hello Igor, First of all, sorry about the late reply. It took me a while to export all shards that weren't available from the osd.2 (1 and 3 were fine, 2 didn't start but i could use `ceph-objectstore-tool ... --op list-pgs` while osd.0 I couldn't even list the pgs, it threw an error right away - more about it later in the email) Two of the unavailable shards, when exporting, ceph-objectstore-tool core dumped with the same issue in the rocksdb, but I should have enough chunks to not need them - just mentioning in case is useful: sh-5.1# ceph-objectstore-tool --data-path /var/lib/ceph/osd --pgid 11.19s2 --op export --file pg.11.19s2.dat /ceph/rpmbuild/BUILD/ceph-20.2.0/src/kv/RocksDBStore.cc: In function 'virtual int RocksDBStore::get(const std::string&, const std::string&, ceph::bufferlist*)' thread 7ff3be4ca800 time 2026-02-04T09:42:00.743877+0000 /ceph/rpmbuild/BUILD/ceph-20.2.0/src/kv/RocksDBStore.cc: 1961: ceph_abort_msg("block checksum mismatch: stored = 246217859, computed = 2155741315, type = 4 in db/170027.sst offset 28264757 size 1417") ceph version 20.2.0 (69f84cc2651aa259a15bc192ddaabd3baba07489) tentacle (stable - RelWithDebInfo) 1: (ceph::__ceph_abort(char const*, int, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)+0xc9) [0x7ff3bf5391fd] 2: (RocksDBStore::get(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, ceph::buffer::v15_2_0::list*)+0x3bc) [0x555667b340bc] 3: (BlueStore::omap_get_values(boost::intrusive_ptr<ObjectStore::CollectionImpl>&, ghobject_t const&, std::set<std::__cxx11::basic_string<char,std::char_traits<char>, std::allocator<char> >, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, std::map<std::__cxx11::basic_string<char,std::char_traits<char>, std::allocator<char> >, ceph::buffer::v15_2_0::list, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, ceph::buffer::v15_2_0::list> > >*)+0x401) [0x555667a25fe1] 4: (PG::peek_map_epoch(ObjectStore*, spg_t, unsigned int*)+0x361) [0x5556675e0101] 5: main() 6: /lib64/libc.so.6(+0x2a610) [0x7ff3be930610] 7: __libc_start_main() 8: _start() *** Caught signal (Aborted) ** in thread 7ff3be4ca800 thread_name:ceph-objectstor ceph version 20.2.0 (69f84cc2651aa259a15bc192ddaabd3baba07489) tentacle (stable - RelWithDebInfo) 1: /lib64/libc.so.6(+0x3fc30) [0x7ff3be945c30] 2: /lib64/libc.so.6(+0x8d03c) [0x7ff3be99303c] 3: raise() 4: abort() 5: (ceph::__ceph_abort(char const*, int, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)+0x186) [0x7ff3bf5392ba] 6: (RocksDBStore::get(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, ceph::buffer::v15_2_0::list*)+0x3bc) [0x555667b340bc] 7: (BlueStore::omap_get_values(boost::intrusive_ptr<ObjectStore::CollectionImpl>&, ghobject_t const&, std::set<std::__cxx11::basic_string<char,std::char_traits<char>, std::allocator<char> >, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, std::map<std::__cxx11::basic_string<char,std::char_traits<char>, std::allocator<char> >, ceph::buffer::v15_2_0::list, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, ceph::buffer::v15_2_0::list> > >*)+0x401) [0x555667a25fe1] 8: (PG::peek_map_epoch(ObjectStore*, spg_t, unsigned int*)+0x361) [0x5556675e0101] 9: main() 10: /lib64/libc.so.6(+0x2a610) [0x7ff3be930610] 11: __libc_start_main() 12: _start() Aborted (core dumped) After importing all shards that I could recover that weren't available, I don't have any "unknown" pgs anymore. I still have lots of PGs in "down" state, which I assume I need to flag both "dead" OSDs as lost to unstuck them. Since it is an operation I cannot go back, I would like to confirm that is indeed the correct next step to take. I have a few questions to understand "what happens" in the next step (marking osd as lost?): Shall I assume that once I flag an OSD as lost, I won't be able to "activate" it since I use encryption when initializing the bluestore OSD, or flagging them as lost won't destroy their unlocking keys? (which means any hope of further extracting data to be gone, mostly on the osd.0 which I couldn't use ceph-objectstore-tool at all since the power loss). I think I should have all the shards from the PGs but just in case, I've managed to make a clone of the osd.0 on a different physical disk (the other reason I took long to answer). But still ceph-objectstore-tool refuses to run: # ceph-objectstore-tool --data-path /var/lib/ceph/osd --op list-pgs Mount failed with '(5) Input/output error' # ls -l /var/lib/ceph/osd total 28 lrwxrwxrwx 1 ceph ceph 50 Feb 4 08:26 block -> /dev/mapper/zNPZJR-i0TZ-6NtK-URto-tjfs-iJRb-GCAYEm -rw------- 1 ceph ceph 37 Feb 4 08:26 ceph_fsid -rw------- 1 ceph ceph 37 Feb 4 08:26 fsid -rw------- 1 ceph ceph 55 Feb 4 08:26 keyring -rw------- 1 ceph ceph 106 Jan 24 00:44 lockbox.keyring -rw------- 1 ceph ceph 6 Feb 4 08:26 ready -rw------- 1 ceph ceph 10 Feb 4 08:26 type -rw------- 1 ceph ceph 2 Feb 4 08:26 whoami Just as information, all except 2 pools in my cluster are "replicated". Pools id 11 and 16 are erasure coded (2+1). If I understood correctly, as long as I have two acting shards (and at most one "NONE"), data should be available (at least in read-only) once I mark the down OSDs as lost. Is that understanding correct? Another information, pools 10 and 15 are the "replicated root pools" before the erasure coded pools were created. Ignoring osd.0 for now, here are the current state of my cluster (mds is intentionally not started while I try to fix the PGs): ### ceph osd lspools 3 .rgw.root 4 default.rgw.log 5 default.rgw.control 6 default.rgw.meta 10 ark.data 11 ark.data_ec 12 ark.metadata 14 .mgr 15 limbo 16 limbo.data_ec 18 default.rgw.buckets.index 19 default.rgw.buckets.data ### ### ceph health # ceph -s cluster: id: 021f058f-dbf3-4a23-adb5-21d83f3f1bb6 health: HEALTH_ERR 1 filesystem is degraded 1 filesystem has a failed mds daemon 1 filesystem is offline insufficient standby MDS daemons available Reduced data availability: 143 pgs inactive, 143 pgs down Degraded data redundancy: 1303896/7149898 objects degraded (18.237%), 218 pgs degraded, 316 pgs undersized 144 pgs not deep-scrubbed in time 459 pgs not scrubbed in time 256 slow ops, oldest one blocked for 1507794 sec, osd.1 has slow ops too many PGs per OSD (657 > max 500) services: mon: 2 daemons, quorum ceph-ymir-mon2,ceph-ymir-mon1 (age 2w) mgr: ceph-ymir-mgr1(active, since 2w) mds: 0/1 daemons up (1 failed) osd: 4 osds: 2 up (since 29m), 2 in (since 4w); 24 remapped pgs data: volumes: 0/1 healthy, 1 failed pools: 12 pools, 529 pgs objects: 2.46M objects, 7.4 TiB usage: 8.3 TiB used, 13 TiB / 22 TiB avail pgs: 27.032% pgs not active 1303896/7149898 objects degraded (18.237%) 306628/7149898 objects misplaced (4.289%) 218 active+undersized+degraded 143 down 98 active+undersized 45 active+clean 19 active+clean+remapped 4 active+clean+remapped+scrubbing+deep 1 active+clean+remapped+scrubbing 1 active+clean+scrubbing+deep ### ceph health ### ceph health detail # ceph health detail HEALTH_ERR 1 filesystem is degraded; 1 filesystem has a failed mds daemon; 1 filesystem is offline; insufficient standby MDS daemons available; Reduced data availability: 143 pgs inactive, 143 pgs down; Degraded data redundancy: 1303896/714 9898 objects degraded (18.237%), 218 pgs degraded, 316 pgs undersized; 144 pgs not deep-scrubbed in time; 459 pgs not sc rubbed in time; 256 slow ops, oldest one blocked for 1508207 sec, osd.1 has slow ops; too many PGs per OSD (657 > max 50 0) [WRN] FS_DEGRADED: 1 filesystem is degraded fs ark is degraded [WRN] FS_WITH_FAILED_MDS: 1 filesystem has a failed mds daemon fs ark has 1 failed mds [ERR] MDS_ALL_DOWN: 1 filesystem is offline fs ark is offline because no MDS is active for it. [WRN] MDS_INSUFFICIENT_STANDBY: insufficient standby MDS daemons available have 0; want 1 more [WRN] PG_AVAILABILITY: Reduced data availability: 143 pgs inactive, 143 pgs down pg 10.11 is down, acting [1,3] pg 10.18 is down, acting [3,1] pg 10.1d is down, acting [1,3] pg 10.1f is down, acting [1,3] pg 11.10 is down, acting [3,1,NONE] pg 11.12 is down, acting [1,NONE,3] pg 11.18 is stuck inactive for 4w, current state down, last acting [1,3,NONE] pg 11.19 is down, acting [3,1,NONE] pg 11.1b is down, acting [1,NONE,3] pg 11.62 is down, acting [NONE,3,1] pg 11.63 is down, acting [3,NONE,1] pg 11.64 is down, acting [NONE,1,3] pg 11.66 is down, acting [NONE,3,1] pg 11.67 is down, acting [1,NONE,3] pg 11.68 is down, acting [3,NONE,1] pg 11.69 is down, acting [NONE,1,3] pg 11.6a is down, acting [1,NONE,3] pg 11.6b is down, acting [NONE,1,3] pg 11.6f is down, acting [NONE,3,1] pg 11.71 is down, acting [1,3,NONE] pg 11.72 is down, acting [1,3,NONE] pg 11.74 is down, acting [NONE,3,1] pg 11.76 is down, acting [1,NONE,3] pg 11.78 is down, acting [3,1,NONE] pg 11.7d is down, acting [NONE,3,1] pg 11.7e is down, acting [NONE,1,3] pg 15.15 is down, acting [1,3] pg 15.16 is down, acting [3,1] pg 15.17 is down, acting [1,3] pg 15.1a is down, acting [3,1] pg 16.1 is down, acting [1,3,NONE] pg 16.4 is down, acting [1,3,NONE] pg 16.b is down, acting [3,NONE,1] pg 16.60 is down, acting [3,1,NONE] pg 16.61 is down, acting [3,1,NONE] pg 16.62 is down, acting [3,NONE,1] pg 16.63 is down, acting [3,NONE,1] pg 16.65 is down, acting [NONE,3,1] pg 16.67 is down, acting [1,NONE,3] pg 16.68 is down, acting [1,NONE,3] pg 16.69 is down, acting [3,1,NONE] pg 16.6a is down, acting [1,3,NONE] pg 16.6c is down, acting [1,3,NONE] pg 16.70 is down, acting [3,NONE,1] pg 16.73 is down, acting [3,NONE,1] pg 16.74 is down, acting [1,3,NONE] pg 16.75 is down, acting [3,1,NONE] pg 16.79 is down, acting [3,NONE,1] pg 16.7a is down, acting [1,3,NONE] pg 16.7e is down, acting [1,3,NONE] pg 16.7f is down, acting [3,NONE,1] [WRN] PG_DEGRADED: Degraded data redundancy: 1303896/7149898 objects degraded (18.237%), 218 pgs degraded, 316 pgs under sized pg 3.18 is stuck undersized for 36m, current state active+undersized, last acting [1,3] ...<snipped for brevity> ### Once again, I cannot thank you enough for looking into my issue. I have the impression that being able to recover the data I need is just around the corner. Although the croit.io blog did mention flagging the osd as lost, I would like to double check it to avoid losing any possibility to recover the data. If there's anything further I could check or if you need full output of the commands, let me know. Thanks in advance. On Tue, 3 Feb 2026 at 10:26, Igor Fedotov <igor.fedotov@croit.io> wrote:

Hi Theo,

you might want to try to use PG export/import using ceph-objectstore-tool.

Please find more details here https://www.croit.io/blog/how-to-recover-inactive-pgs-using-ceph-objectstore...

Thanks,

Igor On 03/02/2026 02:38, Theo Cabrerizo Diem via ceph-users wrote:

:12:18.895+0000 7f0c543eac00 -1 bluestore(/var/lib/ceph/osd) fsck error: free extent 0x1714c521000~978b26df000 intersects allocatedblocks fsck status: remaining 1 error(s) and warning(s)