Hello, We have been experiencing a serious issue with our CephFS backup cluster running quincy (version 17.2.7) on a RHEL8-derivative Linux kernel (Alma8.9, 4.18.0-513.9.1 kernel) where our MDSes for our filesystem are constantly in a "replay" or "replay(laggy)" state and keep crashing. We have a single MDS filesystem called "ceph_backup" with 2 standby MDSes along with a 2nd unused filesystem "ceph_archive" (this holds little to no data) where we are using our "ceph_backup" filesystem to backup our data and this is the one which is currently broken. The Ceph health outputs currently are: root@pebbles-s1 14:05 [~]: ceph -s cluster: id: e3f7535e-d35f-4a5d-88f0-a1e97abcd631 health: HEALTH_WARN 1 filesystem is degraded insufficient standby MDS daemons available 1319 pgs not deep-scrubbed in time 1054 pgs not scrubbed in time services: mon: 4 daemons, quorum pebbles-s1,pebbles-s2,pebbles-s3,pebbles-s4 (age 36m) mgr: pebbles-s2(active, since 36m), standbys: pebbles-s4, pebbles-s3, pebbles-s1 mds: 2/2 daemons up osd: 1380 osds: 1380 up (since 29m), 1379 in (since 3d); 37 remapped pgs data: volumes: 1/2 healthy, 1 recovering pools: 7 pools, 2177 pgs objects: 3.55G objects, 7.0 PiB usage: 8.9 PiB used, 14 PiB / 23 PiB avail pgs: 83133528/30006841533 objects misplaced (0.277%) 2090 active+clean 47 active+clean+scrubbing+deep 29 active+remapped+backfilling 8 active+remapped+backfill_wait 2 active+clean+scrubbing 1 active+clean+snaptrim io: recovery: 1.9 GiB/s, 719 objects/s root@pebbles-s1 14:09 [~]: ceph fs status ceph_backup - 0 clients =========== RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS 0 replay(laggy) pebbles-s3 0 0 0 0 POOL TYPE USED AVAIL mds_backup_fs metadata 1255G 2780G ec82_primary_fs_data data 0 2780G ec82pool data 8442T 3044T ceph_archive - 2 clients ============ RANK STATE MDS ACTIVITY DNS INOS DIRS CAPS 0 active pebbles-s2 Reqs: 0 /s 13.4k 7105 118 2 POOL TYPE USED AVAIL mds_archive_fs metadata 5184M 2780G ec83_primary_fs_data data 0 2780G ec83pool data 138T 2767T MDS version: ceph version 17.2.7 (b12291d110049b2f35e32e0de30d70e9a4c060d2) quincy (stable) root@pebbles-s1 14:09 [~]: ceph health detail | head HEALTH_WARN 1 filesystem is degraded; insufficient standby MDS daemons available; 1319 pgs not deep-scrubbed in time; 1054 pgs not scrubbed in time [WRN] FS_DEGRADED: 1 filesystem is degraded fs ceph_backup is degraded [WRN] MDS_INSUFFICIENT_STANDBY: insufficient standby MDS daemons available have 0; want 1 more When our cluster first ran after a reboot, Ceph ran through the 2 standby MDSes, crashing them all, until it reached the final MDS and is now stuck in this "replay(laggy)" state. Putting our MDSes into debugging mode, we can see that this MDS crashed when replaying the journal for a particular inode (this is the same for all the MDSes and they all crash on the same object): ... 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay for [521,head] had [inode 0x1005ba89481 [...539,head] /cephfs-users/afellows/Ferdos/20210625_real_DDFHFKLMT_KriosIII_K3/cryolo/test_micrographs/ auth fragtree_t(*^2 00*^3 00000*^ 4 00001*^3 00010*^4 00011*^4 00100*^4 00101*^4 00110*^4 00111*^4 01*^3 01000*^4 01001*^3 01010*^4 01011*^3 01100*^4 01101*^4 01110*^4 01111*^4 10*^3 10000*^4 10001*^4 10010*^4 10011*^4 10100*^4 10101*^3 10110*^4 10111*^4 11*^6) v10880645 f(v0 m2024-06-22 T05:41:10.213700+0100 1281276=1281276+0) n(v12 rc2024-06-22T05:41:10.213700+0100 b1348251683896 1281277=1281276+1) old_inodes=8 (iversion lock) | dirfrag=416 dirty=1 0x55770a2bdb80] 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay dir 0x1005ba89481.011011000* 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay updated dir [dir 0x1005ba89481.011011000* /cephfs-users/afellows/Ferdos/20210625_real_DDFHFKLMT_KriosIII_K3/cryolo/test_micrographs/ [2,head] auth v=436385 cv=0/0 state=107374182 4 f(v0 m2024-06-22T05:41:10.213700+0100 2502=2502+0) n(v12 rc2024-06-22T05:41:10.213700+0100 b2120744220 2502=2502+0) hs=32+33,ss=0+0 dirty=65 | child=1 0x55770ebcda80] 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay added (full) [dentry #0x1/cephfs-users/afellows/Ferdos/20210625_real_DDFHFKLMT_KriosIII_K3/cryolo/test_micrographs/FoilHole_27649821_Data_27626128_27626130_20210628_005006_fracti ons_ave_Z124.mrc.teberet7.partial [539,head] auth NULL (dversion lock) v=436384 ino=(nil) state=1610612800|bottomlru | dirty=1 0x557710444500] 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay added [inode 0x1005cd4fe35 [539,head] /cephfs-users/afellows/Ferdos/20210625_real_DDFHFKLMT_KriosIII_K3/cryolo/test_micrographs/FoilHole_27649821_Data_27626128_27626130_20210628_ 005006_fractions_ave_Z124.mrc.teberet7.partial auth v436384 s=0 n(v0 1=1+0) (iversion lock) cr={99995144=0-4194304@538} 0x557710438680] 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.cache.ino(0x1005cd4fe35) mark_dirty_parent 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay noting opened inode [inode 0x1005cd4fe35 [539,head] /cephfs-users/afellows/Ferdos/20210625_real_DDFHFKLMT_KriosIII_K3/cryolo/test_micrographs/FoilHole_27649821_Data_27626128_2762 6130_20210628_005006_fractions_ave_Z124.mrc.teberet7.partial auth v436384 DIRTYPARENT s=0 n(v0 1=1+0) (iversion lock) cr={99995144=0-4194304@538} | dirtyparent=1 dirty=1 0x557710438680] 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay inotable tablev 3112837 <= table 3112837 2024-06-24T13:44:55.563+0100 7f8811c40700 10 mds.0.journal EMetaBlob.replay sessionmap v 1560540883, table 1560540882 prealloc [] used 0x1005cd4fe35 2024-06-24T13:44:55.563+0100 7f8811c40700 -1 /home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos8/DIST/centos8/MACHINE_SIZE/gigantic/release/17.2.7/rpm/el8/BUILD/ceph-17.2.7/src/include/interval_set.h: I n function 'void interval_set<T, C>::erase(T, T, std::function<bool(T, T)>) [with T = inodeno_t; C = std::map]' thread 7f8811c40700 time 2024-06-24T13:44:55.564315+0100 /home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos8/DIST/centos8/MACHINE_SIZE/gigantic/release/17.2.7/rpm/el8/BUILD/ceph-17.2.7/src/include/interval_set.h: 568: FAILED ceph_assert(p->first <= start) ceph version 17.2.7 (b12291d110049b2f35e32e0de30d70e9a4c060d2) quincy (stable) 1: (ceph::__ceph_assert_fail(char const*, char const*, int, char const*)+0x135) [0x7f8821e814a3] 2: /usr/lib64/ceph/libceph-common.so.2(+0x269669) [0x7f8821e81669] 3: (interval_set<inodeno_t, std::map>::erase(inodeno_t, inodeno_t, std::function<bool (inodeno_t, inodeno_t)>)+0x2e5) [0x5576f9bb2885] 4: (EMetaBlob::replay(MDSRank*, LogSegment*, int, MDPeerUpdate*)+0x4377) [0x5576f9eb77b7] 5: (EUpdate::replay(MDSRank*)+0x61) [0x5576f9ebbbd1] 6: (MDLog::_replay_thread()+0x7bb) [0x5576f9e4254b] 7: (MDLog::ReplayThread::entry()+0x11) [0x5576f9af5041] 8: /lib64/libpthread.so.0(+0x81ca) [0x7f8820e6f1ca] 9: clone() I've only included a short section of the crash (this is the first trace in the log with regards to the crash with a 10/20 debug_mds option). We tried deleting the 0x1005cd4fe35 object from the object store using the "rados" command but this did not allow our MDS to successfully replay. From my understanding the journal seems okay as we didn't run out of space for example on our metadata pool and "cephfs-journal-tool journal inspect" doesn't seem to think there is any damage: root@pebbles-s1 13:58 [~]: cephfs-journal-tool --rank=ceph_backup:0 journal inspect Overall journal integrity: OK root@pebbles-s1 14:04 [~]: cephfs-journal-tool --rank=ceph_backup:0 event get --inode 1101069090357 summary Events by type: OPEN: 1 UPDATE: 3 Errors: 0 root@pebbles-s1 14:05 [~]: cephfs-journal-tool --rank=ceph_backup:0 event get --inode 1101069090357 list 2024-06-22T05:41:10.214635+0100 0x51f97d4cfe35 UPDATE: (openc) test_micrographs/FoilHole_27649821_Data_27626128_27626130_20210628_005006_fractions_ave_Z124.mrc.teberet7.partial 2024-06-22T05:41:11.203312+0100 0x51f97d59c848 UPDATE: (check_inode_max_size) test_micrographs/FoilHole_27649821_Data_27626128_27626130_20210628_005006_fractions_ave_Z124.mrc.teberet7.partial test_micrographs/FoilHole_27649821_Data_27626128_27626130_20210628_005006_fractions_ave_Z124.mrc.teberet7.partial 2024-06-22T05:41:15.484871+0100 0x51f97e7344cc OPEN: () FoilHole_27649821_Data_27626128_27626130_20210628_005006_fractions_ave_Z124.mrc.teberet7.partial 2024-06-22T05:41:15.484921+0100 0x51f97e73493b UPDATE: (rename) test_micrographs/FoilHole_27649821_Data_27626128_27626130_20210628_005006_fractions_ave_Z124.mrc.teberet7.partial test_micrographs/FoilHole_27649821_Data_27626128_27626130_20210628_005006_fractions_ave_Z124.mrc I was wondering whether anyone had any advice for us on how we should proceed forward? We were thinking about manually applying these events (via "event apply") where failing that we could erase this problematic event with "cephfs-journal-tool --rank=ceph_backup:0 event splice --inode 1101069090357". Is this a good idea? We would rather not rebuild the entire metadata pool if we could avoid it (once was enough for us) as this cluster has ~9 PB of data on it. Kindest regards, Ivan Clayson -- Ivan Clayson ----------------- Scientific Computing Officer Room 2N249 Structural Studies MRC Laboratory of Molecular Biology Francis Crick Ave, Cambridge CB2 0QH