Hi Greg,
Yes, this was caused by a chain of event. As a cautionary tale, the main
ones were:
1) minor nautilus release upgrade, followed by a rolling node restart
script that mistakenly relied on "ceph -s" for cluster health info,
i.e. it didn't wait for the cluster to return to health before moving
onto restarting the next node, which caused...
2) several pgs to have "unfound object", attempted fix was to "
mark_unfound_lost delete", which caused
3) primary osd (of the pg) to crash with: PrimaryLogPG.cc: 11550: FAILED
ceph_assert(head_obc)
4) only fix we found for the primary pg crashing, was to destroy the
primary osd, and wait for the pg to recover. This worked, or so we thought,
5) however looking at logs, one pg was in
"active+recovery_unfound+undersized+degraded+remapped", I think I may
have "mark_unfound_lost delete" this pg
6) after destroying the primary osd for this pg (oops!) the pg then went
"inactive"
7) to restore access we set "ceph osd pool set ec82pool min_size 8" (on
an EC 8+2 pool), at which point
8) the new primary OSD crashed with FAILED
ceph_assert(clone_size.count(clone)) leaving us with a pg in a very bad
state...
I will see if we can buy some consulting time, the alternative is
several weeks of rsync.
Many thanks again for your advice, it's very much appreciated,
Jake
On 26/03/2020 17:21, Gregory Farnum wrote:
On Wed, Mar 25, 2020 at 5:19 AM Jake Grimmett <jog@xxxxxxxxxxxxxxxxx> wrote:
Dear All,
We are "in a bit of a pickle"...
No reply to my message (23/03/2020), subject "OSD: FAILED
ceph_assert(clone_size.count(clone))"
So I'm presuming it's not possible to recover the crashed OSD
>From your later email it sounds like this is part of a chain of events
that included telling the OSDs to deliberately work around some
known-old-or-wrong state, so while I wouldn't say it's impossible to
fix it's probably not simple and may require buying some consulting
from one of the teams that do that. I don't think I've seen these
errors before anywhere, certainly.
This is bad news, as one pg may be lost, (we are using EC 8+2, pg dump
shows [NONE,NONE,NONE,388,125,25,427,226,77,154] )
Without this pg we have 1.8PB of broken cephfs.
I could rebuild the cluster from scratch, but this means no user backups
for a couple of weeks.
The cluster has 10 nodes, uses an EC 8:2 pool for cephfs data
(replicated NVMe metdata pool) and is running Nautilus 14.2.8
Clearly, it would be nicer if we could fix the OSD, but if this isn't
possible, can someone confirm that the right procedure to recover from a
corrupt pg is:
1) Stop all client access
2) find all files that store data on the bad pg, with:
# cephfs-data-scan pg_files /backup 5.750 2> /dev/null > /root/bad_files
3) delete all of these bad files - presumably using truncate? or is "rm"
fine?
4) destroy the bad pg
# ceph osd force-create-pg 5.750
5) Copy the missing files back with rsync or similar...
This sounds about right.
Keep in mind that the PG will just be a random fraction of the
default-4MB objects in CephFS, so you will hit a huge proportion of
large files. As I assume this is a data pool, keep in mind that any
large files will just show up as a 4MB hole where the missing object
is — this may be preferable to reverting the whole file, or let you
only copy in the missing data if they are logs, or whatever. And you
can use the CephFS metadata to determine if the file in backup is
up-to-date or not.
-Greg
a better "recipe" or other advice gratefully received,
best regards,
Jake
****
Note: I am working from home until further notice.
For help, contact unixadmin@xxxxxxxxxxxxxxxxx
--
Dr Jake Grimmett
Head Of Scientific Computing
MRC Laboratory of Molecular Biology
Francis Crick Avenue,
Cambridge CB2 0QH, UK.
Phone 01223 267019
Mobile 0776 9886539
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Note: I am working from home until further notice.
For help, contact unixadmin@xxxxxxxxxxxxxxxxx
--
Dr Jake Grimmett
Head Of Scientific Computing
MRC Laboratory of Molecular Biology
Francis Crick Avenue,
Cambridge CB2 0QH, UK.
Phone 01223 267019
Mobile 0776 9886539
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To unsubscribe send an email to ceph-users-leave@xxxxxxx
