hi thank you very much； “which works by failing the filesystem” It's means while upgrade all mountpoint can't read and write？ At 2026-05-29 23:01:18, "Anthony D'Atri via dev" <dev@ceph.io> wrote: I’ve struggled a bit understanding this strategy. Help me understand please how completely disabling the filesystem / volume is more tolerable than reducing to one? On May 29, 2026, at 4:30 AM, Dhairya Parmar via dev <dev@ceph.io> wrote:  Hi, There is a solution for this (which works by failing the filesystem), please check the note here - https://docs.ceph.com/en/latest/cephadm/upgrade/#starting-the-upgrade Dhairya Parmar Software Engineer, CephFS On Fri, May 29, 2026 at 3:17 PM 刘先生 via dev <dev@ceph.io> wrote: hi: Our Ceph cluster is deployed using Ceph cephadm and uses multiple MDS daemons. The documentation says that during a cephadm upgrade, the filesystem should be reduced to a single active MDS. However, this is not feasible for us(single mds have not enough mem). Is there a more elegant way to perform the upgrade? Thank you very much.