Hi,
I suffered same bug but testing it on Tentacle upgrade before activating allow_ec_optimizations on existing pools.
I created some pools before upgrade, then upgrade and after setting allow_ec_optimizations oh these pools, I saw this problem.

I would like to activate allow_ec_optimizations for our production ec pools.

Could be possible to have a new release 20.2.1 with those patches included?


Regards
Alfonso Escribano

Joshua Blanch via ceph-users wrote:
We ran into that allow_ec_optimization on a legacy pool and scrubbing issue
recently on 20.2.0.
Wrote down some notes here:
https://docs.clyso.com/blog/2026/04/13/tentacle-v20.2.0-ec-bug/

Specifically it is these trackers which will be in the v20.2.1 release
allow_ec issue:
https://tracker.ceph.com/issues/71642
scrubbing issue:
https://tracker.ceph.com/issues/73184
https://tracker.ceph.com/issues/73260

On Wed, 21 Jan 2026 at 11:17, Eric Dold via ceph-users <ceph-users@ceph.io>
wrote:

Hi Reto, hi Bill

I found this PR that was merged after v20.2.0 was tagged.
https://github.com/ceph/ceph/pull/66021

I'm running Tentacle on Ubuntu Jammy without cephadm, with EC 6+2 and
FastEC enabled.

I'm getting inconsistent PGs with errors like these:
3.336s0 shard 25(5) soid 3:6cc82c0a:::10002107475.0000002c:head : size
700416 != size 696320 from auth oi
3:6cc82c0a:::10002107475.0000002c:head(2830345'2540087
osd.41.2825431:3886213 dirty|data_digest s 4194304 uv 17841689 dd 8f22c13e
alloc_hint [0 0 0])
3.336s0 shard 13(4) soid 3:6cc1c47e:::10002585665.0000045e:10279 : size
700416 != size 696320 from auth oi
3:6cc1c47e:::10002585665.0000045e:10279(2905787'3123318
osd.41.2896446:3729885 dirty|data_digest s 4194304 uv 23445132 dd 365ee4af
alloc_hint [0 0 0] shard_versions={1: 2904402'3115959, 2: 2904402'3115959,
3: 2904402'3115959, 4: 2904402'3115959, 5: 2904402'3115959})
3.336s0 shard 13(4) soid 3:6cc1f637:::20000007ea9.000008fb:bd : size 700416
!= size 696320 from auth oi
3:6cc1f637:::20000007ea9.000008fb:bd(45314'680679 client.124476.0:17244371
dirty|data_digest s 4194304 uv 274244 dd 9f754009 alloc_hint [0 0 0])
3.336 shard 13(4) soid 3:6cc82c71:::1000098dda0.00000237:head : candidate
size 700416 info size 696320 mismatch
3.336 shard 60(1) soid 3:6cde2c17:::20001b3c880.00000000:head : candidate
size 4096 info size 0 mismatch
3.336 shard 13(4) soid 3:6cde2eb0:::100000d68b9.0000000b:head : candidate
size 622592 info size 618496 mismatch

All these errors have something to do with size.

When I restart the OSDs the cluster is healthy until some scrub picks this
up again.
The data seems ok.

It seems like the fix is not in the tentacle release.
Is there a future release with fixes for this planned?

Regards
Eric


On Fri, 5 Dec 2025 at 16:34, Reto Gysi via ceph-users <ceph-users@ceph.io>
wrote:

Hi Bill

Am Fr., 5. Dez. 2025 um 10:02 Uhr schrieb Bill Scales <
bill_scales@uk.ibm.com>:

Hi Reto,

Sorry to hear about your problems with turning on ec optimizations.
I've
led the team that developed this feature, so we are keen to help
understand
what happened to your system.

Your configuration looks fine as far as being supported with ec
optimizations. The daemons (mons, osds and mgr) need to be running
tentacle
code to use this feature, there is no requirement to update any of your
clients.

Do you have any more examples of the inconsistent objects logs that you
can share with me?

There was a bug that we fixed late in the development cycle which was
scrubbing incorrectly reporting a size mismatch for objects written
prior
to turning on optimizations. This is because prior to turning on
optimizations objects are padded to a multiple of the stripe_width,
afterwards objects are no longer padded. The scrub code was
occasionally
getting confused and incorrectly reporting an inconsistency. In this
case
the scrub was reporting false positive errors - there was nothing wrong
with the data and no problems accessing the data. I notice the log you
shared in the email was for a size mismatch, I'm interested whether all
the
logs were for mismatched sizes. We will do some further work to confirm
that the fix is in the 20.2.0 tentacle release and that there are no
problems with the back port.

As far I could see the errors where all about the mismatched sizes.


You also mention that you saw some OSD crashes. Do you have any further
information about these?

I just could cause another crash with starting up a windows VM, and
doing a
WIndows file history backup to a drive that is on an RBD Image on pool
rbd_ecpool where I had the allow_ec_optimization flag enabled.

<disk type="network" device="disk">
  <driver name="qemu" type="raw" cache="writethrough" io="threads"
discard="unmap" detect_zeroes="unmap"/>
  <auth username="admin">
    <secret type="ceph" uuid="878b0bc5-c471-4ec6-a92a-f65282ffbdf6"/>
  </auth>
  <source protocol="rbd" name="rbd/game_windows_backup_drive" index="3">
    <host name="zephir" port="6789"/>
  </source>
  <target dev="vdd" bus="virtio"/>
  <alias name="virtio-disk3"/>
  <address type="pci" domain="0x0000" bus="0x00" slot="0x02"
function="0x0"/>
</disk>

 root@zephir:~# ceph -s
 cluster:
   id:     27923302-87a5-11ec-ac5b-976d21a49941
   health: HEALTH_WARN
           2 osds down
           Reduced data availability: 49 pgs inactive
           Degraded data redundancy: 15722192/79848340 objects degraded
(19.690%), 246 pgs degraded, 247 pgs undersized

 services:
   mon:           3 daemons, quorum zephir,debian,raspi (age 20h)
[leader:
zephir]
   mgr:           zephir.enywvy(active, since 21h), standbys:
debian.nusuye
   mds:           3/3 daemons up, 3 standby
   osd:           18 osds: 16 up (since 5m), 18 in (since 3d); 8 remapped
pgs
   cephfs-mirror: 2 daemons active (2 hosts)
   rbd-mirror:    2 daemons active (2 hosts)
   rgw:           1 daemon active (1 hosts, 1 zones)
   tcmu-runner:   5 portals active (2 hosts)

 data:
   volumes: 3/3 healthy
   pools:   25 pools, 450 pgs
   objects: 17.52M objects, 62 TiB
   usage:   116 TiB used, 63 TiB / 179 TiB avail
   pgs:     10.889% pgs not active
            15722192/79848340 objects degraded (19.690%)
            197 active+undersized+degraded
            183 active+clean
            49  undersized+degraded+peered
            15  active+clean+scrubbing
            5   active+clean+scrubbing+deep
            1   active+undersized

 io:
   client:   1.7 KiB/s rd, 1023 B/s wr, 1 op/s rd, 0 op/s wr

root@zephir:~# ceph osd status
ID  HOST     USED  AVAIL  WR OPS  WR DATA  RD OPS  RD DATA  STATE
0  debian  11.2T  5289G      0        0       0        0   exists,up
1  zephir  11.6T  4846G      0        0       0        0   exists
2  zephir  10.7T  5827G      0        0       2        4   exists,up
3  zephir  11.0T  5497G      0        0       0        0   exists
4  zephir   159G  1376G      0        0       2        0   exists,up
5  zephir   120G  1415G      0        0       0        0   exists,up
6  debian  11.3T  5200G      0        0       1        0   exists,up
7  zephir   305G  1230G      0        0       0        0   exists,up
8  zephir  10.9T  5594G      0        0       0        0   exists,up
9  zephir  11.9T  4616G      0        0       0        0   exists,up
10  zephir   235G  1300G      0        0       0        0   exists,up
11  zephir   223G  1312G      0        0       0        0   exists,up
12  zephir  11.0T  5479G      0        0       0        0   exists,up
13  debian   118G   631G      0        0       3        8   exists,up
14  debian   345G  1190G      0        0       0        0   exists,up
15  debian  11.4T  5079G      0        0       0        0   exists,up
16  debian   554G  3029G      0        0       3        8   exists,up
17  debian  12.5T  5874G      0        0       1        0   exists,up
root@zephir:~#

I attached the log of osd.1 to
https://filebin.net/jwvs6kuqrc7hx8id

Best Regards,

Reto




          
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