This manifests itself as the following, as reported by lsblk(1). Note the missing Ceph LVM volume on the 6th NVME disk:
$ cat sos_commands/block/lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 1.8T 0 disk |-sda1 8:1 0 512M 0 part /boot/efi `-sda2 8:2 0 1.8T 0 part |-foobar--vg-root 253:0 0 1.8T 0 lvm / `-foobar--vg-swap_1 253:1 0 976M 0 lvm [SWAP] nvme0n1 259:0 0 1.8T 0 disk `-ceph--c576f63e--dfd4--48f7--9d60--6a7708cbccf6-osd--block--9fdd78b2--0745--47ae--b8d4--04d9803ab448 253:6 0 1.8T 0 lvm nvme1n1 259:1 0 1.8T 0 disk `-ceph--6eb6565f--6392--44a8--9213--833b09f7c0bc-osd--block--a7d3629c--724f--4218--9d15--593ec64781da 253:5 0 1.8T 0 lvm nvme2n1 259:2 0 1.8T 0 disk `-ceph--c14f9ee5--90d0--4306--9b18--99576516f76a-osd--block--bbf5bc79--edea--4e43--8414--b5140b409397 253:4 0 1.8T 0 lvm nvme3n1 259:3 0 1.8T 0 disk `-ceph--a821146b--7674--4bcc--b5e9--0126c4bd5e3b-osd--block--b9371499--ff99--4d3e--ab3f--62ec3cf918c4 253:3 0 1.8T 0 lvm nvme4n1 259:4 0 1.8T 0 disk `-ceph--2e39f75a--5d2a--49ee--beb1--5d0a2991fd6c-osd--block--a1be083e--1fa7--4397--acfa--2ff3d3491572 253:2 0 1.8T 0 lvm nvme5n1 259:5 0 1.8T 0 disk -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1828617 Title: Hosts randomly 'losing' disks, breaking ceph-osd service enumeration Status in systemd package in Ubuntu: Confirmed Bug description: Ubuntu 18.04.2 Ceph deployment. Ceph OSD devices utilizing LVM volumes pointing to udev-based physical devices. LVM module is supposed to create PVs from devices using the links in /dev/disk/by-dname/ folder that are created by udev. However on reboot it happens (not always, rather like race condition) that Ceph services cannot start, and pvdisplay doesn't show any volumes created. The folder /dev/disk/by-dname/ however has all necessary device created by the end of boot process. The behaviour can be fixed manually by running "#/sbin/lvm pvscan --cache --activate ay /dev/nvme0n1" command for re-activating the LVM components and then the services can be started. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1828617/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp