Hello Chris,
Great to hear, few questions.
Once you have injected the bluefs_preextend_wal_files to false, are you just rebuilding the OSD's that failed? Or are you going through and rebuilding every OSD even the working one's?
Or does setting the bluefs_preextend_wal_files value to false and leaving the OSD running fix the WAL automatically?
Thanks
---- On Sat, 23 May 2020 15:53:42 +0800 Chris Palmer <chris.palmer@xxxxxxxxx> wrote ----
Hi Ashley
Igor has done a great job of tracking down the problem, and we have
finally shown evidence of the type of corruption it would produce in
one of my WALs. Our feeling at the moment is that the problem can be
detoured by setting bluefs_preextend_wal_files to false on affected
OSDs while they are running (but see below), although Igor does note
that there is a small risk in doing this. I've agreed a plan of
action based on this route, recreating the failed OSDs, and then
cycling through the others until all are healthy. I've started this
now, and so far it looks promising, although of course I have to
wait for recovery/rebalancing. This is the fastest route to
recovery, although there other options.
I'll post as it progresses. The good news seems to be that there
shouldn't be any actual data corruption or loss, providing that this
can be done before OSDs are taken down (other than as part of this
process). My understanding is that there will some degree of
performance penalty until the root cause is fixed in the next
release and preextending can be turned back on. However it does seem
like I can get back to a stable/safe position without waiting for a
software release.
I'm just working through this at the moment though, so please don't
take the above as any form of recommendation. It is important not to
try to restart OSDs though in the meantime. I'm sure Igor will
publish some more expert recommendations in due course...
Regards, Chris
On 23/05/2020 06:54, Ashley Merrick
wrote:
Thanks Igor,
Do you have any idea on a e.t.a or plan for people that are
running 15.2.2 to be able to patch / fix the issue.
I had a read of the ticket and seems the corruption is
happening but the WAL is not read till OSD restart, so I
imagine we will need some form of fix / patch we can apply to
a running OSD before we then restart the OSD, as a normal OSD
upgrade will require the OSD to restart to apply the code
resulting in a corrupt OSD.
Thanks
---- On Sat, 23 May 2020 00:12:59 +0800 Igor Fedotov mailto:ifedotov@xxxxxxx wrote ----
Status update:
Finally we have the first patch to fix the issue in
master:
https://github.com/ceph/ceph/pull/35201
And ticket has been updated with root cause
analysis:https://tracker.ceph.com/issues/45613On 5/21/2020 2:07 PM, Igor
Fedotov wrote:
@Chris - unfortunately it looks like the corruption is
permanent since
valid WAL data are presumably overwritten with another
stuff. Hence I
don't know any way to recover - perhaps you can try
cutting
WAL file off which will allow OSD to start. With some
latest ops lost.
Once can use exported BlueFS as a drop in replacement for
regular DB
volume but I'm not aware of details.
And the above are just speculations, can't say for sure if
it helps...
I can't explain why WAL doesn't have zero block in your
case though.
Little chances this is a different issue. Just in case -
could you
please search for 32K zero blocks over the whole file? And
the same for
another OSD?
Thanks,
Igor
> Short update on the issue:
>
> Finally we're able to reproduce the issue in master
(not octopus),
> investigating further..
>
> @Chris - to make sure you're facing the same issue
could you please
> check the content of the broken file. To do so:
>
> 1) run "ceph-bluestore-tool --path
<path-to-osd> --our-dir <target
> dir> --command bluefs-export
>
> This will export bluefs files to <target dir>
>
> 2) Check the content for file db.wal/002040.log at
offset 0x470000
>
> This will presumably contain 32K of zero bytes. Is
this the case?
>
>
> No hurry as I'm just making sure symptoms in Octopus
are the same...
>
>
> Thanks,
>
> Igor
>
> On 5/20/2020 5:24 PM, Igor Fedotov wrote:
>> Chris,
>>
>> got them, thanks!
>>
>> Investigating....
>>
>>
>> Thanks,
>>
>> Igor
>>
>> On 5/20/2020 5:23 PM, Chris Palmer wrote:
>>> Hi Igor
>>> I've sent you these directly as they're a bit
chunky. Let me know if
>>> you haven't got them.
>>> Thx, Chris
>>>
>>> On 20/05/2020 14:43, Igor Fedotov wrote:
>>>> Hi Cris,
>>>>
>>>> could you please share the full log prior
to the first failure?
>>>>
>>>> Also if possible please set
debug-bluestore/debug bluefs to 20 and
>>>> collect another one for failed OSD
startup.
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Igor
>>>>
>>>>
>>>> On 5/20/2020 4:39 PM, Chris Palmer wrote:
>>>>> I'm getting similar errors after
rebooting a node. Cluster was
>>>>> upgraded 15.2.1 -> 15.2.2
yesterday. No problems after rebooting
>>>>> during upgrade.
>>>>>
>>>>> On the node I just rebooted, 2/4 OSDs
won't restart. Similar logs
>>>>> from both. Logs from one below.
>>>>> Neither OSDs have compression
enabled, although there is a
>>>>> compression-related error in the log.
>>>>> Both are replicated x3. One has data
on HDD & separate WAL/DB on
>>>>> NVMe partition, the other is
everything on NVMe partition only.
>>>>>
>>>>> Feeling kinda nervous here - advice
welcomed!!
>>>>>
>>>>> Thx, Chris
>>>>>
>>>>>
>>>>>
>>>>> 2020-05-20T13:14:00.837+0100
7f2e0d273700 3 rocksdb:
>>>>>
[table/block_based_table_reader.cc:1117] Encountered error
while
>>>>> reading data from compression
dictionary block Corruption: block
>>>>> checksum mismatch: expected 0, got
3423870535 in db/000304.sst
>>>>> offset 18446744073709551615 size
18446744073709551615
>>>>> 2020-05-20T13:14:00.841+0100
7f2e1957ee00 4 rocksdb:
>>>>> [db/version_set.cc:3757] Recovered
from manifest
>>>>> succeeded,manifest_file_number is 312,
>>>>> next_file_number is 314,
last_sequence is 22320582, log_number is
>>>>> 309,prev_log_number is
0,max_column_family is
>>>>> 0,min_log_number_to_keep is 0
>>>>>
>>>>> 2020-05-20T13:14:00.841+0100
7f2e1957ee00 4 rocksdb:
>>>>> [db/version_set.cc:3766] Column
family [default] (ID 0), log
>>>>> number is 309
>>>>>
>>>>> 2020-05-20T13:14:00.841+0100
7f2e1957ee00 4 rocksdb: EVENT_LOG_v1
>>>>> {"time_micros": 1589976840843199,
"job": 1, "event":
>>>>> "recovery_started", "log_files":
[313]}
>>>>> 2020-05-20T13:14:00.841+0100
7f2e1957ee00 4 rocksdb:
>>>>> [db/db_impl_open.cc:583] Recovering
log #313 mode 0
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 3 rocksdb:
>>>>> [db/db_impl_open.cc:518]
db.wal/000313.log: dropping 9044 bytes;
>>>>> Corruption: error in middle of record
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 3 rocksdb:
>>>>> [db/db_impl_open.cc:518]
db.wal/000313.log: dropping 86 bytes;
>>>>> Corruption: missing start of
fragmented record(2)
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 4 rocksdb:
>>>>> [db/db_impl.cc:390] Shutdown:
canceling all background work
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 4 rocksdb:
>>>>> [db/db_impl.cc:563] Shutdown complete
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 -1 rocksdb: Corruption:
>>>>> error in middle of record
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 -1
>>>>> bluestore(/var/lib/ceph/osd/ceph-9)
_open_db erroring opening db:
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 1 bluefs umount
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 1 fbmap_alloc
>>>>> 0x55daf2b3a900 shutdown
>>>>> 2020-05-20T13:14:00.937+0100
7f2e1957ee00 1 bdev(0x55daf3838700
>>>>> /var/lib/ceph/osd/ceph-9/block) close
>>>>> 2020-05-20T13:14:01.093+0100
7f2e1957ee00 1 bdev(0x55daf3838000
>>>>> /var/lib/ceph/osd/ceph-9/block) close
>>>>> 2020-05-20T13:14:01.341+0100
7f2e1957ee00 -1 osd.9 0 OSD:init:
>>>>> unable to mount object store
>>>>> 2020-05-20T13:14:01.341+0100
7f2e1957ee00 -1 ESC[0;31m ** ERROR:
>>>>> osd init failed: (5) Input/output
errorESC[0m
>>>>>
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