From a26ae56658b70eb026e098ee08d2f392df19fcc0 Mon Sep 17 00:00:00 2001 From: Pierre Riteau Date: Fri, 21 Nov 2025 13:45:19 +0100 Subject: [PATCH 1/2] ceph: document bumping minimum client version This can unlock some features on older clusters, such as the upmap balancer mode. --- doc/source/operations/upgrading-ceph.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/doc/source/operations/upgrading-ceph.rst b/doc/source/operations/upgrading-ceph.rst index c0c82057f..5e1bf4333 100644 --- a/doc/source/operations/upgrading-ceph.rst +++ b/doc/source/operations/upgrading-ceph.rst @@ -171,6 +171,21 @@ versions``. Once confirmed, run the following command: ceph config set osd bluestore_elastic_shared_blobs 0 +Finally, verify the value of ``ceph osd get-require-min-compat-client``. On +older Ceph deployments, it may still be set to ``jewel``, which would prevent +using the `upmap balancer mode +`__ which +requires ``luminous`` or later. Similarly, the more recent `read balancer +`__ requires +``reef``. + +Run ``ceph features`` to identify client versions and consider setting the +minimum to an appropriate value: + +.. code-block:: console + + ceph osd set-require-min-compat-client reef + Upgrade Cephadm =============== From d97af15981b9f6c194e50931fef727469ccc29d5 Mon Sep 17 00:00:00 2001 From: Pierre Riteau Date: Fri, 21 Nov 2025 13:53:46 +0100 Subject: [PATCH 2/2] ceph: document known issues for Squid --- doc/source/operations/upgrading-ceph.rst | 31 ++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/doc/source/operations/upgrading-ceph.rst b/doc/source/operations/upgrading-ceph.rst index 5e1bf4333..2dd5a0de0 100644 --- a/doc/source/operations/upgrading-ceph.rst +++ b/doc/source/operations/upgrading-ceph.rst @@ -9,6 +9,37 @@ The Ceph release series is not strictly dependent upon the StackHPC OpenStack release, however this configuration does define a default Ceph release series and container image tag. The default release series is currently |ceph_series|. +Known issues +============ + +Slow ceph-volume activate +------------------------- + +A large slowdown of ``ceph-volume activate`` has been reported on version +19.2.3 (`bug 73107 `__). + +On Reef, a host with 15 OSDs was measured taking around 10 seconds to activate +all OSDs while exiting maintenance mode. On Squid 19.2.3, a host with 22 OSDs +was measured taking 2 minutes to activate all OSDs. + +This bug may be a blocker for deployments with large number of OSDs per host. + +Elastic Shared Blob crash +------------------------- + +There is a `known bug causing OSDs created on Squid to crash +`__. To avoid it, `disable the +Elastic Shared Blob feature +`__ before +any OSDs are created or replaced: + +.. code-block:: bash + + ceph config set osd bluestore_elastic_shared_blobs 0 + +This needs to be done after the upgrade is complete as the option is not +available on Reef. + Prerequisites =============