I was using a setup using FCP-disks -> Multipath -> LVM not being mounted anymore after an upgrade from 18.04 to 20.04.
I was seeing these errors at boot - I thought that is ok to sort out duplicates:
May 28 09:00:43 s1lp05 lvm[746]: WARNING: Not using device /dev/sdd1 for PV q1KTMM-fkpM-Ewvm-T4qd-WgO8-hV79-qXpUpb.
May 28 09:00:43 s1lp05 lvm[746]: WARNING: Not using device /dev/sdi1 for PV q1KTMM-fkpM-Ewvm-T4qd-WgO8-hV79-qXpUpb.
May 28 09:00:43 s1lp05 lvm[746]: WARNING: Not using device /dev/sdn1 for PV q1KTMM-fkpM-Ewvm-T4qd-WgO8-hV79-qXpUpb.
May 28 09:00:43 s1lp05 lvm[746]: WARNING: PV q1KTMM-fkpM-Ewvm-T4qd-WgO8-hV79-qXpUpb prefers device /dev/sds1 because device was seen first.
May 28 09:00:43 s1lp05 lvm[746]: WARNING: PV q1KTMM-fkpM-Ewvm-T4qd-WgO8-hV79-qXpUpb prefers device /dev/sds1 because device was seen first.
May 28 09:00:43 s1lp05 lvm[746]: WARNING: PV q1KTMM-fkpM-Ewvm-T4qd-WgO8-hV79-qXpUpb prefers device /dev/sds1 because device was seen first.
But then later auto-activation fails on duplicates
May 28 09:00:56 s1lp05 systemd[1]: Starting LVM event activation on device 253:8...
May 28 09:00:56 s1lp05 lvm[1882]: pvscan[1882] PV /dev/mapper/mpathd-part1 is duplicate for PVID q1KTMMfkpMEwvmT4qdWgO8hV79qXpUpb on 253:8 and 8:49.
May 28 09:00:57 s1lp05 systemd[1]: lvm2-pvscan@253:8.service: Main process exited, code=exited, status=5/NOTINSTALLED
May 28 09:00:57 s1lp05 systemd[1]: lvm2-pvscan@253:8.service: Failed with result 'exit-code'.
May 28 09:00:57 s1lp05 systemd[1]: Failed to start LVM event activation on device 253:8.
And finally giving up:
May 28 09:02:12 s1lp05 systemd[1]: dev-vgdisks-lv_tmp.device: Job dev-vgdisks-lv_tmp.device/start timed out.
lvdisplay reported the devices then as LV Status NOT available
It seems LVM now scans more (or the kernel presents more) devices. I didn't have these issues on 18.04.