Append to EC pool object (docs vs. reality)

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	Hello, Ceph users,

my erasure-coded pool is inconsistent with the documentation,
apparently existing objects cannot be appended to.
The documentation states the following:

================
https://docs.ceph.com/en/latest/rados/operations/erasure-code/
By default, erasure-coded pools work only with operations that perform
full object writes and appends (for example, RGW).
================

Appends do not work for me:

$ ceph osd pool create test-ec erasure k5m2
pool 'test-ec' created
$ echo -n 12345678 | rados --pool test-ec put testobj -
$ rados --pool test-ec stat testobj
test-ec/testobj mtime 2025-09-05T12:51:20.000000+0200, size 8
$ echo -n 12345678 | rados --pool test-ec put testobj - --offset 8
error putting test-ec/testobj: (95) Operation not supported
$ echo -n 12345678 | rados --pool test-ec append testobj -
error appending test-ec/testobj: (95) Operation not supported

When I enable the allow_ec_overwrites flag, everything works as expected:

$ ceph osd pool set test-ec allow_ec_overwrites true 
set pool 73 allow_ec_overwrites to true
$ echo -n 12345678 | rados --pool test-ec put testobj - --offset 8
$ echo -n 12345678 | rados --pool test-ec append testobj -
$ rados --pool test-ec stat testobj
test-ec/testobj mtime 2025-09-05T12:54:30.000000+0200, size 24

Should the documentation be fixed somehow (maybe appending works only
at certain block sizes or whatever), or am I doing something incorrect?
My cluster is Ceph 19.2.2.

Thanks,

-Yenya

-- 
| Jan "Yenya" Kasprzak <kas at {fi.muni.cz - work | yenya.net - private}> |
| https://www.fi.muni.cz/~kas/                        GPG: 4096R/A45477D5 |
    We all agree on the necessity of compromise. We just can't agree on
    when it's necessary to compromise.                     --Larry Wall
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