Hi, For new clusters one of the first things I do is to disable messenger v1: ceph config set mon ms_bind_msgr1 false However, that is not enough, as a restart of the monitors will leave v1 enabled in the monmap. Why is that? That looks like a bug to me. Therefore I explicitly set the addrs and port of the monitors, i.e.: ceph mon set-addrs stefan-ceph-test01 $ip:3300 Be careful not to make a typo, that will ruin your day, see [1]. This immediately disables v1 and a new monmap is created. All good, however ... When a monitor is removed, say mon1, and added again, the new mon is added with both a v1 and a v2 address. I don't want that, I want to disable legacy v1 permanently. How do I do that? Adding: [mon] ms_bind_msgr1 = false to /etc/ceph/ceph.conf does not help either. When I performed a test this morning on a fresh 18.2.4 cluster (remove a mon, add it back again) to reproduce this issue the v1 was enabled again on two monitors (a third was left with only v2). Repeating the "ceph mon set-addrs" command removes the v1 binding again. But I would like to avoid messing around with this, triggering monmaps / elections, especially when making an error with this brings your cluster to a halt [1]. In what Ceph release will v1 be disabled by default on new clusters? Gr. Stefan [1] https://tracker.ceph.com/issues/54744