From 349dbb0ad8b51cdf7fe0e49a35fef52870964e73 Mon Sep 17 00:00:00 2001
From: Pierre Riteau <pierre@stackhpc.com>
Date: Mon, 10 Nov 2025 18:12:23 +0100
Subject: [PATCH] Document Ceph Squid bug and workaround

---
 doc/source/operations/upgrading-ceph.rst | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/doc/source/operations/upgrading-ceph.rst b/doc/source/operations/upgrading-ceph.rst
index e9fc2f679..c0c82057f 100644
--- a/doc/source/operations/upgrading-ceph.rst
+++ b/doc/source/operations/upgrading-ceph.rst
@@ -159,6 +159,18 @@ versions``. Once confirmed, run the following command:
 
    ceph osd require-osd-release squid
 
+.. warning::
+
+   There is a `known bug causing OSDs created on Squid to crash
+   <https://tracker.ceph.com/issues/70390>`__. To avoid it, `disable the
+   Elastic Shared Blob feature
+   <https://docs.clyso.com/blog/#squid-deployed-osds-are-crashing>`__ before
+   any OSDs are created or replaced:
+
+   .. code-block:: bash
+
+      ceph config set osd bluestore_elastic_shared_blobs 0
+
 Upgrade Cephadm
 ===============