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
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